Renner is the son of Valerie Cearley (née Tague) and Lee Renner, who raised him in Modesto, California. Renner graduated from Modesto's Fred C. Beyer High School in 1989. He studied computer science and criminology at Modesto Junior College before taking a drama class as an elective and decided to pursue acting.
Renner made his film debut in the 1995 comedy National Lampoon's Senior Trip as an underachieving student. Despite the film's critical acclaim, he went on to guest star on two television shows, Deadly Games and Strange Luck, and had a minor role as Paul Hewitt's friend in the television film A Friend's Betrayal (Brian Austin Green).