The accident happened around 12:45 a.m. on the 5400 block of Woodland Avenue.
The victim was crossing the street when he was struck by a 2012 Honda Civic and thrown about 50 feet, police say.
He suffered multiple injuries and was rushed to the Hospital of the University of Pennsylvania in extremely critical condition.
Witnesses say the driver and a passenger got out of the striking car and fled on foot.
The two males were taken into custody about five blocks from the scene.
A female passenger is also being questioned by police.
The 20-year-old driver was charged with driving under the influence, police say.
He was also driving with a suspended license.
There is no word yet on whether speed was a factor in the crash.
Philadelphia Police Chief Insp. Scott Small says the suspect is facing serious charges, including leaving the scene of an accident.