Michael Fahy, a 17-year veteran of the fire department, died after he was struck in the head by building debris sent flying to the street, Fire Department Commissioner Daniel Nigro told reporters at New York-Presbyterian/Allen Hospital.
"We lost a hero today and our members are all saddened," said Nigro, who was visibly emotional. "He was a star, a brave man."
New York Mayor Bill de Blasio said Fahy, whose father was a fire battalion chief with the city and a contemporary of Nigro's, leaves behind three children, ages 6, 8 and 11.
The Uniformed Firefighters Association of Greater New York said he was the highest-ranking New York fire official to die in the line of duty since the Sept. 11, 2001 attacks.
The blast just after 7 a.m. EDT also injured 20 people, including nine firefighters and six police officers, many of whom were transported to the hospital, fire officials said. Their conditions were not immediately disclosed, and investigators have not determined the cause of the blast.
Without elaborating, Police Commissioner James O'Neill said detectives were investigating reports of a marijuana "grow home" in the area.
Firefighters investigated reports of a possible gas leak in the area for about an hour before the explosion tore the roof off the two-story home, Nigro said.
Fahy was directing operations, including evacuating nearby buildings, when he was struck in the head and elsewhere by the debris, the commissioner said.
Police rushed the battalion chief to the hospital, where he was pronounced dead. All of the victims were injured while in the street, Nigro said.