Dermoth Mattison,

Founder & Executive Director

Mr. 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. With nearly 20 years of experience in charter school leadership, he is a lifelong advocate for educational equity and opportunity.
Mr. Mattison has led schools that consistently outperform local districts and close achievement gaps for underserved students. During the 2023–24 school year, 99 percent of scholars at South Shore met growth goals in reading and math on the NWEA MAP assessment. In 2024–25, the school ranked in the 94th percentile in reading and 88th percentile in math nationally on the same assessment, reflecting both exceptional growth and high achievement. Before founding South Shore, he served as a principal where his school consistently outperformed the local district and was recognized for strong student growth and academic achievement.

He founded South Shore and developed its full academic and cultural model from the ground up. He led the charter development process and engaged families, educators, and community leaders to ensure the school reflected local needs and aspirations. A strategic leader, he builds high-capacity teams, coaches emerging leaders, and designs systems that align vision with daily execution. His leadership is grounded in the school’s core values: Integrity, Grit, Resilience, Excellence, Accountability, and Tenacity. These values form the belief that every scholar and staff member can proudly say, “I am GREAT.”

Mr. Mattison oversees the school’s operations and finances, ensuring strong systems, sound stewardship, and clean financial audits since inception. He holds 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 wonderful children.

Mr. Mattison is committed to expanding access to high-quality public charter schools in high-needs communities across Long Island, New York.

Executive Leadership

Georgina Garcia
Chief of Staff

Georgina Garcia has a successful track record of serving as a highly effective operational leader in the New York charter sector. She graduated from the State University of New York at Albany with a Bachelor of Arts in Sociology and Criminal Justice. Ms. Garcia has experience in organizational leadership, project management, government compliance and community-based organization development. Fluent in Spanish, she is passionate about public service and making a positive impact in the South Shore Charter School community.

Arsenio Heslop
Principal

Arsenio Heslop has served in the field of education for nearly a decade. He previously served as an instructional leader and classroom teacher in New York City Public Schools. Mr. Heslop received a Master’s of Science with a double major in Childhood Education and Special Education from the Metropolitan College of New York. He also holds a Master’s Degree in School and District Leadership from Touro College. Mr. Heslop is passionate about serving the South Shore Charter School community as Principal.

Ryan Miller
Director of Operations & Finance

Ryan Miller has served in the field of management, finance, and auditing for nearly a decade. Mr. Miller’s guided years of education were received internationally, receiving up to a Bachelor’s of Science in Management Studies Accounting at the University of the West Indies. He also holds a Master of Science in Taxation from Baruch College. He has a passion for serving the community and developing students into socially responsible leaders.

Board of Trustees

Keith Brown

Board Chair

Kanika Mobley​

Board Secretary

Karlene Cowan​

Treasurer

Arturo Cuchillas

Trustee

Michelle Haynes

Trustee

Kevin Warren

Trustee

Miguel Garrick

Trustee