Tempe police say 19-year-old Alexander Alcantar was arrested Wednesday and booked into jail on suspicion of felony hit and run.
Police say Alcantar allegedly was driving his wife's car when he collided with another vehicle on April 21.
The other vehicle spun out of control onto the sidewalk and hit a 14-year-old pedestrian, who was transported to a hospital with extremely serious injuries.
Police say Alcantar left the scene and never returned.
Detectives believed Alcantar lived in the neighborhood and kept searching for the red car involved in the crash and finally found it.
It's unclear if he has a lawyer yet.