Harold KL Castle Foundation

What Harold KL Castle Foundation does

The Harold K.L. Castle Foundation is a private philanthropic foundation established in 1962 by Harold Kainalu Long Castle using wealth from Kaneohe Ranch and other Ko'olaupoko land assets, headquartered in Kailua, Windward O'ahu, Hawai'i. The Foundation deploys approximately 5% of its endowment annually through grants concentrated in four interconnected program areas: K-12 Public Education & Mobility, Nearshore Ocean Resiliency, Climate Resiliency (the first new strategic pillar in over 20 years, launched October 2023), and Strengthening Windward O'ahu Communities. Annual grant commitments have ranged from $5.1M (2024) to $9.2M (2025), with cumulative K-12 public education grants since inception totaling nearly $37M across 345 awards.

The Foundation's portfolio includes flagship initiatives such as the Hawai'i Youth Apprenticeship Network (HYAN), the Hawai'i Renewable Learning Fund (a zero-interest loan program co-designed with Social Finance), the Pilina Fund participatory grantmaking vehicle, the Youth Voice Hawai'i research series with 'A'ali'i Alliance, the Middle School Transition Partnership Fund, and a seven-grant Skilled Trades Pre-Apprenticeship portfolio. Its grantee mix spans the Hawai'i Department of Education, the University of Hawai'i System, Kamehameha Schools, The Nature Conservancy of Hawai'i, Kua'āina Ulu Auamo, Maui United Way, and dozens of small community-based nonprofits. Grant administration runs through the FLUXX platform. The Foundation does not sell products or services; its operating model is endowment-funded grantmaking plus non-financial convening and capacity-building support.

Following 22 years under President and CEO Terry George, the Foundation underwent a leadership transition effective July 1, 2025, with two new leaders appointed to oversee an active portfolio that has increasingly emphasized workforce pathways, climate preparedness, and statewide geographic reach beyond its original Windward O'ahu base.

Name

Harold KL Castle Foundation

Legal name

Harold K.L. Castle Foundation

Website

https://castlefoundation.org

Company type

Private

Founded year

1962

Operating status

Operating

Headcount range

11–50 employees

Short description

The Harold K.L. Castle Foundation is a 1962-vintage private philanthropic foundation headquartered in Kailua, Hawai'i that deploys ~5% of its endowment annually as grants across K-12 public education, nearshore marine conservation, climate resiliency, and Windward O'ahu community strengthening, serving nonprofits, schools, and statewide intermediaries.

Ownership category

akta.pro rank

Product category

Philanthropic Grantmaking

NAICS

Grantmaking Foundations (813211)

akta.pro primary industry

Private Foundations (BPAGAKAA)

akta.pro secondary industries

Education Grantmaking Foundations (BPAGAKAK), Environmental & Climate Grantmaking Foundations (BPAGAKAM)

Keywords

• Philanthropic foundation
• Grantmaking programs
• Community grant funding
• Education grant programs
• Marine conservation funding

Headquarters

HQ city

Kailua

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Others

Distribution channels1 record

Marketing channels7 records

Core offering

The Harold K.L. Castle Foundation is a private nonprofit foundation that awards grants to nonprofit organizations, educational institutions, and community groups in Hawaii. Its grantmaking focuses on Public Education & Mobility, Nearshore Ocean Resiliency, Climate Resiliency, and Strengthening Windward O'ahu Communities, deploying roughly $5–9 million annually through competitive RFPs, unsolicited grants, and participatory grantmaking (Pilina Fund).

Product overview

The Harold K.L. Castle Foundation is a private philanthropic organization (not a technology product company) that operates multiple interconnected grantmaking programs and initiatives focused on improving outcomes for Hawai'i's youth and communities. The foundation's core programs include: Public Education Redesign and Enhancement (supporting career pathways, apprenticeships, and school-business partnerships), the Hawai'i Youth Apprenticeship Network (HYAN) for workforce development, Youth Voice Hawai'i research initiative, the Middle School Transition Partnership Fund, the Hawai'i Renewable Learning Fund (zero-interest loans), and Skilled Trades Pre-Apprenticeship Programs. The foundation also funds environmental programs including Nearshore Marine Resource Conservation and the Climate Resiliency Strategy. Community resilience is supported through the Ko'olau Pilina Fund and Windward Youth Leadership Fund. All grant administration is managed through the Fluxx online portal. The foundation's investments span Public Education, Climate Resiliency, Marine Conservation, and Strengthening Windward O'ahu Communities.

Differentiator

Problem solved

Functional benefit

Products and services

• Public Education Redesign and Enhancement Grants Annual grant program supporting K-12 public education improvement, career pathways, youth apprenticeships, and post-secondary transitions for Hawaii organizations. Recipients include Center for Tomorrow's Leaders, Design Thinking Hawaii, Hawaii Chamber of Commerce Foundation, and workforce development initiatives.
• Youth Voice Hawai'i Multi-year research initiative producing annual reports with findings and recommendations about opportunity youth in Hawaii.
• Hawai'i Youth Apprenticeship Network (HYAN) Statewide initiative helping young people ages 14-24 access apprenticeship opportunities through sector partnerships, pre-apprenticeship programs, and direct employer connections in high-demand fields including skilled trades, healthcare, and green jobs.
• Middle School Transition Partnership Fund Grant program supporting transition activities between elementary and middle school or middle and high school. Partnership teams can receive up to $7,500 for planning and execution of transition activities over 18 months.
• Hawai'i Renewable Learning Fund Zero-interest, no-fee loan program for low-income juniors and seniors in Hawaii, launched in partnership with Social Finance to help students complete educational programs they cannot afford.
• Skilled Trades Pre-Apprenticeship Programs Portfolio of seven grants supporting skilled trades training for young people in Hawaii, with focus on underrepresented and rural communities. Programs include construction, electrical, plumbing, HVAC, welding, maritime, and automotive pathways.
• Ko'olau Pilina Fund Participatory grantmaking initiative building community resilience in Windward O'ahu communities from Kahuku to Makapu'u. Eight community leaders from across Windward O'ahu make funding decisions, having distributed $641,270 to 64 projects.
• Windward Youth Leadership Fund Grant program enabling youth to make a difference in their community while gaining valuable life experience. Provides funding for youth-led initiatives and leadership development activities in Windward O'ahu.
• Nearshore Marine Resource Conservation Grant program improving ocean governance and management through community-based approach ensuring healthier, more resilient and sustainable nearshore marine ecosystems. Includes support for community-driven work, fishpond restoration, water-quality monitoring, and fishing industry partnerships.
• Climate Resiliency Strategy Foundation's first new strategy in over 20 years, focusing on helping Hawaii communities be prepared and adaptive to climate change impacts through leveraging both funding and non-financial resources across all foundation programs.
• FLUXX Grant Management Portal Online grants management platform (Fluxx) used by the foundation for grant applications, reporting, and administration. Grantseekers can access the portal for online inquiry and application submission.

Quantifiable outcome

• 398 students enrolled at Windward CC (20% increase); 71% growth in male enrollment; 40% growth in Native Hawaiian enrollment
• +4 more outcomes

Segments5 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

39 partnerships are on record, tiered major, core and minor.

• Harry & Jeannette Weinberg FoundationmajorStrategic or Co-development Partner · 1 January 2022The Harry & Jeannette Weinberg Foundation partnered with the Harold K.L. Castle Foundation on the Skilled Trades initiative, recruiting community-based nonprofit partners, trade associations, employers, and training institutions to increase access to skilled trades careers for young, diverse people from underrepresented and rural communities in Hawaii.
• Kamehameha SchoolscoreStrategic or Co-development Partner · 1 January 2020Kamehameha Schools partnered with the Foundation on the Pilina Fund, a participatory grantmaking initiative supporting Windward O'ahu communities during the pandemic. Kamehameha Schools co-funded this effort alongside the Foundation to build community resilience and distribute $641,270 to 64 projects. Also partnered on $2.1M grant to expand Windward Community College's early college efforts.
• Hawai'i P-20coreStrategic or Co-development Partner · 1 June 2014Hawai'i P-20 is a statewide partnership between the Executive Office of Early Learning, the state Department of Education, and the University of Hawai'i System. The Foundation has provided major grants ($1,327,387) to support the Early College Initiative and programs aimed at increasing college attainment to 55% of working-age adults by 2025. P-20 leads the Soar Higher program ($2.3M) and coordinates career pathway efforts across the state.
• PENCIL FoundationminorStrategic or Co-development PartnerInspired by the PENCIL Foundation in Nashville, the Foundation provided multi-year support to nonprofit organizations to connect teachers and students with industry professionals for work-based learning in Hawaii.
• Hawai'i Workforce PipelinemajorStrategic or Co-development PartnerOne of several regional intermediary organizations funded by the Foundation to expand work-based learning. Along with the Chamber of Commerce and Kaua'i Economic Development Board, dramatically expanded student access to internships, career fairs, job shadows, and mock interviews across Hawaii.
• Hawai'i Chamber of Commerce FoundationmajorStrategic or Co-development PartnerRegional intermediary partner that navigated different organizational cultures to directly coordinate connections between teachers, students, and industry professionals. Part of the Foundation's strategy to expand equitable work-based learning across Hawaii's school districts.
• Kaua'i Economic Development BoardmajorStrategic or Co-development PartnerRegional intermediary partner on the work-based learning initiative, expanding student opportunity to connect with industry professionals across Hawaii's school districts.
• Associated Builders and ContractorsmajorImplementation/ SI/ Consulting PartnerTrade association representing 200 members across Hawaii, selected for the Skilled Trades initiative. Will increase the number of youth pre-qualified for accelerated entry into state-approved apprenticeship programs (carpentry, plumbing, HVAC) by running 21 cohorts of 10-15 students each across Oahu, Hawaii island and Maui.
• Honolulu Community CollegemajorImplementation/ SI/ Consulting PartnerSelected for the Skilled Trades initiative to run a 6-week summer academy for high school juniors exploring three trades across two weeks each. Priority trades include carpentry technology, welding, automotive technology, diesel mechanics technology, architectural engineering, and occupational and environmental safety management. 200 students recruited from Windward and Leeward regions of Oahu.
• Building Industry Association (BIA) Foundation HawaiimajorImplementation/ SI/ Consulting PartnerSelected for the Skilled Trades initiative to run the Green Community Pre-Apprenticeship Construction Training Program with two cohorts (12 and 8 students ages 17-24) for a paid pre-apprenticeship covering carpentry, plumbing and HVAC with emphasis on green principles and sustainable practices.
• Marimed FoundationmajorImplementation/ SI/ Consulting PartnerKaneohe-based nonprofit selected for the Skilled Trades initiative to introduce high school seniors to maritime industry careers through a five-month curriculum and USGS certifications aboard their 96-foot vessel, the SS Makani Olu.
• Makaha Cultural Learning CentermajorImplementation/ SI/ Consulting Partner10-year-old Leeward nonprofit selected for the Skilled Trades initiative, proposing a 100-hour training program for solar panel installation and maintenance in two cohorts of approximately 40 youth each, drawing on relationships at Waianae and Nanakuli High Schools.
• Hawaii Electricians Training FundmajorImplementation/ SI/ Consulting PartnerSelected for the Skilled Trades initiative to run a pre-apprenticeship interim credential (5 courses over 6-12 months) to combat high dropout rates. Students completing the program receive direct entry to the apprenticeship along with up to a year of credit.
• Pearl Harbor Aviation MuseumminorImplementation/ SI/ Consulting PartnerSelected to receive a modest planning grant (full training program deemed too complex) to develop a high school aircraft maintenance certification program alongside Hawaiian Airlines, with planning work to develop stronger partnerships with area high schools and Honolulu Community College.
• The Nature Conservancy of Hawai'icoreStrategic or Co-development PartnerMajor marine conservation partner receiving $400,000 grant to build state and local marine resource management in at least 15 coastal communities. Work includes Kiholo fishpond restoration, community water-quality monitoring, protocol development, fishing industry collaboration, community-based marine management area designations, and seafood product development.
• Tri-Isle Resource Conservation & Development CouncilmajorStrategic or Co-development PartnerReceived $80,000 grant to improve the health of West Maui's marine ecosystem by reducing land-based pollution over one year.
• Hawai'i Seafood CouncilmajorStrategic or Co-development PartnerReceived $55,000 grant to develop seven training programs including tours of the fish auction at Pier 38 for high school, college, and graduate-level classes related to fisheries and marine biology.
• Kua'āina Ulu Auamo (KUA)majorStrategic or Co-development PartnerGrassroots nonprofit organization established to support the E Alu Pu network of over three dozen communities working on nearshore ocean management across Hawaii. E Alu Pu began as a convening of communities wrestling with similar marine management challenges and grew into a statewide movement.
• Learning for ActionmajorStrategic or Co-development PartnerConsulting partner that conducted student interviews and research for the Youth Voice Hawai'i initiative, providing the Foundation with deeply researched insights on student aspirations, concerns, and barriers to post-secondary planning.
• 'A'ali'i AlliancemajorStrategic or Co-development PartnerPartner in the Youth Voice Hawai'i initiative, providing a platform for young people to share their perspectives and hopes for the future. Also co-hosted a listening tour across Windward O'ahu with the Foundation during the pandemic.
• University of Hawaii FoundationmajorStrategic or Co-development PartnerMultiple grants including $50,000 to support the Stupski Maui Relief Fund for UH students affected by wildfires, and multiple education grants totaling hundreds of thousands of dollars for youth apprenticeship programs, teacher development, and post-secondary transition initiatives.
• Hawaii Chamber of Commerce FoundationminorStrategic or Co-development PartnerReceived a $50,000 challenge grant to support the Business Relief Fund to help businesses affected by the Maui Wildfires.
• Hawai'i People’s FundminorStrategic or Co-development PartnerReceived $50,000 flexible grant to build capacity to provide relief to those directly impacted by wildfires on Maui and amplify their voice in decision-making through the 'Maui Aloha: The People's Response' initiative.
• Hui O Wa'a KauluaminorStrategic or Co-development PartnerReceived $50,000 flexible grant to build capacity to provide wildfire relief and to help replace canoes lost in the Lahaina wildfires.
• Maui United WaymajorStrategic or Co-development PartnerReceived $100,000 grant (over two years) as flexible funding to help provide relief to those directly impacted by the wildfires, support community organizations, and help in the recovery and rebuilding phases.
• Mālama Learning CentermajorStrategic or Co-development PartnerPartnership to produce television segments for 'Outside Hawai'i,' a 20+ year show reaching 55,000 households monthly. Funded to produce 8 segments humanizing DLNR employees and supporting the Holomua Initiative, and an additional 8 segments covering the Maui Navigation Team, Makai Watch, and the Hawai'i Ocean Stewardship Fee.
• Hawaii State Department of EducationcoreStrategic or Co-development PartnerMajor long-term partner for public education initiatives. Foundation works with HIDOE on career pathways, middle school transitions, post-secondary planning, teacher development, and literacy improvement across Hawaii's public schools.
• University of Hawai'i SystemcoreStrategic or Co-development PartnerMajor education partner. Foundation supports UH College of Education programs, early college expansion, youth apprenticeship pathways, emergency hire teacher licensure, and UH student support following the Maui wildfires.
• Hui O HauulaminorImplementation/ SI/ Consulting PartnerCommunity Action Team for the Windward Oahu Eviction Prevention Program serving the Kahuku-Kaaawa area. Point of Contact: Dynaka Merino. Provides application assistance, legal help, mediation services, and financial counseling.
• Adventist Health CastleminorImplementation/ SI/ Consulting PartnerCommunity Action Team for the Windward Oahu Eviction Prevention Program serving the Kaneohe-Kailua area. Point of Contact: Tiffany Ijima. Helps connect at-risk residents with emergency rent assistance and rapid rehousing support.
• KEY ProjectminorImplementation/ SI/ Consulting PartnerCommunity Action Team for the Windward Oahu Eviction Prevention Program serving the Kualoa-Kaneohe area. Point of Contact: Allison Skillbred. Provides housing assistance, application support, and connections to community resources.
• Waimanalo Health CenterminorImplementation/ SI/ Consulting PartnerCommunity Action Team for the Windward Oahu Eviction Prevention Program serving Waimanalo. Point of Contact: Latia Konohia Badiyo. Assists residents with application for emergency housing and utility assistance.
• Hui Mahiai 'AinaminorImplementation/ SI/ Consulting PartnerCommunity Action Team for the Windward Oahu Eviction Prevention Program serving Waimanalo. Point of Contact: Pili Sampaio. Provides housing navigation and assistance for at-risk Waimanalo residents.
• Center for Tomorrow's LeadersmajorStrategic or Co-development PartnerMulti-year partner working to strengthen persuasive communication and writing of ~300 high school students annually ($80,000 in 2024). In 2026, received $95,000 for Skills of the Future to design an employer-validated credential.
• 50CAN / HawaiiKidsCANmajorStrategic or Co-development PartnerReceived $250,000 unrestricted core operating grant in 2025 for strategic advocacy supporting HawaiiKidsCAN's mission to improve public education through policy advocacy.
• New Teacher CentermajorStrategic or Co-development PartnerReceived $180,000 in 2024 to work alongside the Hawaii Department of Education in building support and resources to enable complex area leaders to bring effective mathematics coaching to school communities.
• Social FinancemajorStrategic or Co-development PartnerFoundation partnered with Social Finance to launch the Hawai'i Renewable Learning Fund - a zero-interest, no-fee loan program for low-income juniors and seniors to complete workforce training programs they cannot afford.
• College Summit / PeerForwardmajorStrategic or Co-development PartnerReceived $224,985 in 2024 to scale a promising peer counseling model to four additional high schools, helping students navigate post-secondary transitions.
• Florida State University Research FoundationminorStrategic or Co-development PartnerReceived grants totaling $88,339 to deliver Fundamentals of Literacy Coaching Train-the-Trainer Workshop and ongoing literacy coaching for the Hawaii Department of Education to improve early literacy.

Scale indicators18 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Kamehameha Schools: Major Hawaii-focused private foundation and trust with deep focus on Hawaiian education, Native Hawaiian culture, and community well-being. A direct co-funder with the Castle Foundation on Pilina Fund and Windward Community College early college initiatives, making it the most operationally comparable peer in the Hawaii ecosystem.
• Hawai'i Community Foundation: Hawaii's largest community foundation, coordinating Maui Strong Fund (raised millions, distributed $5M for wildfire recovery). Operates as a peer funder across the same education, climate, and community resilience issue areas as the Castle Foundation in Hawaii.
• Harry & Jeannette Weinberg Foundation: Mid-sized private family foundation with deep Hawaii footprint and similar focus on workforce development, housing, and community needs. Active co-funding partner with the Castle Foundation on the Skilled Trades initiative, making it a directly comparable operational peer.
• Surdna Foundation: Family foundation with comparable mission focus on environment, education, and inclusive economies. Similar size profile and catalytic grantmaking philosophy makes it a strong comparable for how the Castle Foundation's strategy and impact model is evaluated externally.
• Jessie Ball duPont Foundation: Mid-sized private family foundation with similar geographic concentration strategy and emphasis on community building, education, and place-based grantmaking. A natural structural comparable for evaluating Castle Foundation's operating model and endowment deployment.

Broad incumbents

• The Nature Conservancy (Hawai'i): Largest nonprofit conservation organization with deep Hawaii marine and coastal programming; received $400K Castle Foundation grant for marine management in 15+ coastal communities. Comparable in marine conservation grantmaking, though operates globally rather than Hawaii-only.
• William and Flora Hewlett Foundation: Major national education and environment foundation operating at significantly larger scale. Comparable in deep K-12/post-secondary education strategy and emphasis on evidence-based grantmaking, providing a benchmark for how Castle's approach might evolve at scale.
• Ford Foundation: Largest U.S. philanthropic foundation with deep education and economic opportunity portfolios. While operating globally, its place-based community development and education-to-employment work provides strategic context for how the Castle Foundation's regional model could evolve.

Emerging players

• Barr Foundation: Family foundation with strong focus on public education and climate mitigation, deploying comparable multi-million dollar annual grantmaking. Overlaps with the Castle Foundation's education strategy and youth pathways work.
• Strada Education Foundation: Education-focused national foundation with strong alignment to the Castle Foundation's post-secondary transition and workforce development agenda. Overlaps in apprenticeship pathways and 'Enlist, Employ or Enroll' post-high-school navigation strategies.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xx.com/HaroldKLCastle
• YouTubeyoutube.com/user/hklcastle
• Facebookfacebook.com/pages/Harold-KL-Castle-Foundation/56297956988
• LinkedInlinkedin.com/company/harold-k.l.-castle-foundation

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds

Investors

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M&A

Investments

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Frequently asked questions about Harold KL Castle Foundation