Bergin, who was 9 at the time, works at Ladder 157 in Brooklyn. “I wanted to be a firefighter for as long as I can remember,” Bergin Jr., 32, said, in a post on the FDNY’s Instagram page.

The flames spread after the tenants of the apartment where the fire started left the door open, FDNY officials said. Three people, including a baby and a 4-year-old boy, were left clinging to life ...