First responders raced to the First Ave. construction site near E. 117 St. about 10:40 a.m. after getting reports that the hardhat had been struck by falling debris.
Medics rushed him to Harlem Hospital with a minor cut to his head.
He was talking to his colleagues as the ambulance took him away, a construction supervisor said.
Police and the Department of Buildings were investigating.
It was not immediately clear if the high winds that buffeting the city Tuesday morning played a role in the accident, officials said.