The NYPD identified him as a former family doctor at the hospital, Henry Bello, who sources said was bent on revenge after being fired for harassment two years ago.
Bello, 45, was found on the 17th floor, dead of a self-inflicted gunshot wound, with an M-16-type rifle with the gun nearby, NYPD Commissioner James O'Neil.
He had apparently tried to set himself on fire, as well, the commissioner said.
The body of a female doctor was found near Bello's body, O'Neill said. Both she and Bello were pronounced dead at the scene, he said.
At least two of the wounded were also doctors, the commissioner said.
The shootings began around 2:45 p.m. on the 16th and 17th floors of the non-profit hospital at 173rd Street and Grand Concourse.
Bello, 45, apparently used a rifle that he'd hidden under a lab coat. He was carrying ID, the NYPD said.
Hospital doctors and other personnel refused evacuation orders to stay and assist the wounded throughout the incident, Aaron Katersky of ABCNewsRadio reported.
Click here to follow Daily Voice Pelham and receive free news updates.