The fatal collision was reported about 11:45 p.m. at the intersection of Pico Boulevard and Westmoreland Avenue, according to the Los Angeles Police Department.
The victim, identified by coroner's officials as Carlos Granados Jovel of Los Angeles, died at the scene.
After the second crash, at Wilshire Boulevard and Hoover Street, the driver was taken into custody, investigators said. Details of the latter incident were not available.
The suspect's name was not immediately released. He faces charges of driving under the influence and vehicular manslaughter.