It happened at the Spring Creek Towers, formerly Starrett City, with the outage affecting the entire 46-building complex home to 15,000 residents.
A massive FDNY response -- with 150 firefighters and 30 pieces of apparatus -- were on scene to deal with the problem.
"This is not an unusual occurrence for this complex," FDNY Deputy Chief Wayne Cartwright said. "We come here once a year for a power problem. Every time, it requires a large commitment from the FDNY."
The initial call came in around 10 a.m., with power fully restored at 12:30 p.m.
Firefighters had to search about 100 elevators and rescued at least 30 people.
Everyone has been accounted for, and four people reportedly sought medical attention for minor injuries.