Dermoth Mattison is the Founder and Executive Director of South Shore Charter School, a nationally recognized public charter school founded in 2021 and serving families in Central Islip, New York and its surrounding communities. He designed and oversees the school’s academic program and the systems that drive its operations, finance, and facilities management, while developing the leaders needed to sustain the school’s success and future growth.
Under his leadership, South Shore has achieved exceptional academic results. In Spring 2026, 99% of scholars were proficient on the New York State ELA exam and 100% were proficient in Math. Since its inception, South Shore scholars have also performed at the 99th percentile nationally in both ELA and Math on the NWEA MAP assessment.
Mr. Mattison is known for building high-functioning school environments from the ground up by bringing strong instruction, intentional culture, and disciplined operations together into one cohesive model. South Shore has maintained strong financial and operational health, including clean financial audits, annual operating surpluses, strong enrollment, and effective structures for staffing and compliance. His work is grounded in the belief that strong systems, consistently executed, create the conditions for both scholar achievement and adult excellence.
Mr. Mattison regularly shares his experience building and leading high-performing schools with leaders and organizations across the country. He has shared his perspective through SUNY’s More Great Seats for Kids podcast and at national convenings including the National Charter Schools Conference and the National Association of Charter School Authorizers Conference.
His leadership is grounded in South Shore’s core values of Integrity, Grit, Resilience, Excellence, Accountability, and Tenacity, captured in the belief that every scholar and staff member can proudly say, “I am GREAT.”
Mr. Mattison holds master’s degrees in Childhood Education and Educational Leadership, along with New York State certifications in teaching and school leadership. He is currently pursuing a doctoral degree in educational leadership. He is a proud husband and father of three and remains focused on building and expanding access to high-performing public education across Long Island.
Georgina Rodriguez
Chief of Staff
Arsenio Heslop
Principal
Ryan Miller
Director of Operations & Finance
Ryan Miller serves as Director of Operations & Finance where he leads the financial and operational systems that support the school’s academic program. His work includes financial management, budgeting, compliance, facilities, and the operational systems needed to support a growing school community. Mr. Miller brings nearly a decade of experience in operations, management, finance, and auditing.
Board Chair
Board Secretary
Trustee
Trustee
