A security officer at 271 Cadman Plaza East saw the hawk's collision on a security camera feed, the U.S. Attorney's Office said on Twitter.
Special Security Officer George Slater and Support Services Supervisor Marc Caffray then found the injured hawk on the sidewalk on Adams Street, the office said. The bird appeared stunned and unable to fly.
Caffray used his smartphone to locate a wildlife specialist to help.
David Karopkin, a practicing attorney who also happens to be a certified wildlife rehabilitator, responded to the call. The Daily News reported that Karopkin faced some challenges getting the hawk to cooperate but ultimately succeeded trapping him.
Karopkin "raced over and transported the hawk to @wildbirdfund in Manhattan for emergency medical treatment," the U.S. Attorney's Office tweeted. "The hawk is on the mend and we salute George, Marc and David for a job well done."
Red-tailed hawks have become an almost common sight in New York in recent years.
Every year, tens of thousands of birds fly in to the city's buildings and die, according to New York City Audubon. In December, the City Council voted to require new construction to install so-called bird-friendly glass.