[10][11] A son of Italian-American immigrants, Cassano was born in the Carroll Gardens section of Brooklyn, New York,[4][12] and lives on Staten Island.

[5] He was also instrumental in rebuilding the department after 343 firefighters died as a result of the September 11 attacks, after which he was named Chief of Operations and served at this post,[5][3][16] succeeding Daniel A. Nigro until 2006.

[18] Mr. Cassano serves as Senior Advisor to the law firm of Pitta & Baione LLP, who assist with 9/11 compensation fund claims.

Cassano and his wife, Theresa (née Wallace),[19] live in the Huguenot section of Staten Island, where they raised their family.

[21] Cassano practices the Transcendental Meditation technique and recommends it as a stress management tool for first responders and firefighters who deal with crisis and trauma, "going from 0-100 every single day.