Mayor Bill de Blasio joined hundreds of New York's Bravest at a Staten Island church Thursday to mourn their fallen colleague, Lt. Gordon Matthew Ambelas.

Ambelas, 40, a 14-year veteran with the FDNY, died Saturday night while fighting a blaze in Williamsburg. De Blasio described the father of two as an inspiration for the city, not only for his work on duty but also for his dedication to his loved ones.

"When you think about the things that make a hero, it's all those things -- the selflessness, it's the devotion, it's the bravery," he said. "But there's also a heroism in doing the right thing by your own family."

A two-alarm fire broke out on the 19th floor at 75 Wilson St. after an AC cord sparked the blaze. Ambelas' unit, Ladder Co. No. 119, was the first on the scene and he became trapped in a cluttered bedroom while searching for victims.

"Matt's only thoughts were for the safety of others. He plunged into the fire to search for life. He led from the front, as great leaders do, as he always did," De Blasio said.

Ambelas, who was honored last month for saving a boy who got stuck in a roll-down gate, was the first FDNY member to die in the line of duty in two years.

The lieutenant's widow, Nanette, wrote a eulogy but was too distraught to read it so a family friend did instead, according to news reports.