Authorities say 23-year-old Raul Rios was hit by a car early Sunday morning on East Post Road in White Plains.
Surveillance video showed the black, late-model Mercedes that hit him.
The driver fled the scene and is still on the loose.
Two people who came to his aid were then struck by a second hit-and-run driver.
They were not seriously hurt.
Police later arrested the second driver and charged him with DWI.