Louis Perez, 65, died at the scene of the accident, police said. His granddaughter, Nyanna Aquil, and 24-year-old Kristian Leka were rushed to Jacobi Medical Center, where they died.
Nyanna was dressed as a cat for Halloween, and had a nose and whiskers painted on her face. She lived just a block away from her grandfather in the Van Nest neighborhood of the Bronx, and family said the two were close.
Nyanna's mother, Natalia Perez, told NBC 4 New York that her father died pushing another of her girls, an 8-year-old, to safety. Louis Perez was a loving and devoted grandfather who went out of his way for her girls every day, and it was in character that he died trying to save them, she said.
A 3-year-old girl, a 9-year-old girl and a 21-year-old woman were taken to Jacobi Medical Center with injuries that police said weren't life-threatening.
The 52-year-old driver of the car was taken to Jacobi Medical Center and was in stable condition, police said.
The accident occurred at about 4:50 p.m. at the intersection of Morris Park and Radcliff avenues. Witnesses told NBC 4 New York that the car went airborne after leaving the street and came to rest in the front yard of a home after hitting the group.
"It was horrible," said witness Kristina Dejesus, who described trying to help one of the victims at the grisly scene. "When she finally came to, I'm just like, 'Stay still! Don't move! Don't move!' And I turned back, I'm just yelling at everyone, 'Call 911!'"
The black 2011 Dodge Charger that struck the victims was traveling west on Morris Avenue when it bumped the rear of a Toyota Camry and crossed into the oncoming lane before launching onto the sidewalk and striking the six pedestrians, investigators said.
A cab driver told NBC 4 New York that the car had rammed his cab a few times before veering off the road. He said he doesn't know why he was being rammed.
--Ida Siegal contributed to this report.