Gleason, who played four years of lacrosse at Shoreham-Wading River High School, died Wednesday at Albany Medical Center from a traumatic head injury after suffering a fall at his home just days earlier.
He was 41.
Gleason was part of the team that won the state championship in 2002 before graduating in 2003. He went on to play two years of lacrosse at Adelphi University before finishing his collegiate career and graduating from the University at Albany in 2007.
He took over the Saints lacrosse program in 2018 and was just named Eastern College Athletic Conference Division I men's lacrosse coach of the year after leading the program to its fourth Metro Atlantic Athletic Conference Tournament Championship.
Gleason is survived by his wife of 12 years, Jaclyn, their three children, including daughter Kennedy and sons Penn and Tate, as well as his parents, Kevin and Susan, according to Siena University.
The school is holding a public funeral service on Saturday at 11 a.m. inside the UHY Center on the Siena University campus.