Raheem Turner, 20, of Staten Island is charged with felony assault.
Police say Turner and two other people beat up 34-year-old firefighter Matthew Dugan after Dugan got upset at the group for laughing at his girlfriend near the Staten Island Ferry's Whitehall Terminal.
The beating left Dugan in critical condition.
Police are still searching for the other two people involved.
Dugan was assigned to Ladder 15 in Lower Manhattan. He's been with the New York Fire Department for three years.