Hundreds of city firefighters lined the streets Friday for the funeral for a veteran FDNY lieutenant who suffered a fatal heart attack after a busy 24-hour shift.

Lt. Brian “Sully” Sullivan — the father of two daughters and an admired member of the FDNY’s elite Special Operations Command with 27 years on the job — was just 54 years old.

He had just finished a day-long tour, during which he responded to seven emergencies and a kitchen fire, when he died on Aug. 10, officials said.

“He had a personality that would truly light up a room,” close friend Lt. Scott Altman of Battalion 8 said of his mentor in a eulogy.

The FDNY Emerald Society Pipes and Drums played as a fire truck from Sullivan’s Bronx-based Squad Company 41 carried the fireman’s casket up Still Road to Sacred Heart Church.

Inside, Altman remembered how once or twice a year, “Sully” would personally whip up an elaborate dinner.

“If you were lucky enough to be working that night, you knew you were in for a treat, as he would prepare and cook the entire meal himself,” he said.

“Not that he didn’t trust us. But those of us who knew Sully knew he could be a little bit of a perfectionist in the kitchen,” he said with a laugh.

“As we sat around the table laughing and joking, I’d occasionally look over and look up and see Sully cooking away with a smile on his face.

“It wasn’t that he was tired of getting food poisoning from some of the cooks in the firehouse, but rather, he was giving his men the night off.

“We were always his No. 1 priority at work,” he said.

“His positivity, encouragement and laugh would turn a tough day into a shift we could go away from feeling proud,” Altman added.

“Brian represented everything that made our job great.”

Sullivan was a fearless and highly trained member of Special Operations, said FDNY Commissioner Daniel Nigro.

“Fires, collapses, confined-space rescues and intricate operations, these dangerous and hazardous incidents were Brian’s specialty,” Nigro said.

Mayor Bill de Blasio told mourners, “I want to extend my condolences to the entire Sullivan family, to his sister Katherine, his brothers John and Daniel and his entire extended family — and to that strong second family, the FDNY, who feels this loss so deeply today.”

Additional reporting by Laura Italiano