Dermoth Mattison is the Founder and Executive Director of South Shore Charter School, a nationally recognized public charter school serving communities across Long Island, New York. Under his leadership, the school has achieved exceptional academic outcomes, with scholars performing at the 99th percentile nationally in both ELA and Math on the NWEA MAP assessment since inception.
He is known for building high-functioning school environments from the ground up, aligning strong instruction, intentional culture, and disciplined operations into a cohesive and sustainable model. At South Shore, he has established systems that drive academic success while ensuring organizational stability, including clean financial audits, annual operating surpluses, and effective structures for staffing, enrollment, compliance, and daily operations. His work reflects a belief that strong systems, consistently executed, create the conditions for both scholar achievement and adult excellence.
Through this approach, South Shore Charter School has become a high-performing and trusted option for families on Long Island, expanding access to rigorous, values-driven public education and demonstrating what is possible when schools are built with clarity, consistency, and purpose.
Prior to founding South Shore, Mr. Mattison served as a principal, where his school consistently outperformed the local district and was recognized for strong student growth and achievement.
Mr. Mattison regularly contributes to national conversations on effective and sustainable charter school models, with organizations and conferences seeking his perspective on building schools that are both high-performing and durable over time. He has shared insights through SUNY’s More Great Seats for Kids podcast and at convenings such as the National Charter Schools Conference and the National Association of Charter School Authorizers (NACSA) Conference.
His leadership is grounded in South Shore’s core values: Integrity, Grit, Resilience, Excellence, Accountability, and Tenacity, captured in the belief that every scholar and staff member can proudly say, “I am GREAT.”
He holds master’s degrees in Childhood Education and Educational Leadership, along with New York State certifications in teaching and school leadership, and is currently pursuing a doctoral degree in educational leadership. He is a proud husband and father of three and remains focused on building high-performing public schools that create lasting opportunity across Long Island.
