Aaron was born in Richmond, Canada and is the son of homemaker Linda and engineer Rick. He has a twin brother, Shawn Ashmore. The twins were discovered by a talent agent in a club called "Multiple Birth Association" where their mother was a regular. The twins started out in commercials, sometimes by themselves or sometimes together. He is known for playing ‘Marc Hall’ in "Prom Queen: The March Hall Story". He has also appeared in the films "Safe", "A Separate Peace" and "A Bear Named Winnie," and played the recurring role of ‘Troy Vandegraff" in the TV series ‘Veronica Mars’.