"I just prayed that I'd catch her," Stephen St. Bernard recalled after rescuing the child on Monday.
"'Please let me catch her, please let me catch her.' That's all I could say," he added.
St. Bernard said he was walking home from work when he observed a commotion outside the Coney Island housing complex. He saw the girl standing on the air conditioning unit, seemingly unafraid and moving about.
It wasn't clear how she got there, but witnesses told the Daily News that she crawled out by pulling aside the unit's accordion-like plastic partitions that keep the air conditioner secured in the window.
An amateur video shows St. Bernard yelling up to the girl, telling her to go back inside when she suddenly falls and he catches her in his arms.
"I picked her up and carried her. ... She kept looking around. She never closed her eyes. She never lost consciousness," he said.
The girl was taken to a Coney Island hospital with minor injuries. St. Bernard, a father of four, suffered a torn tendon in his shoulder.
Neighbors said the girl was a special needs child.
Police said no charges were filed against the parents.