Duval was born in Detroit, Michigan. His family moved to California in 1974, where his sister, Terry, was born. He attended Gladstone High School in Covina (1986–89), as well as Mira Costa High School in Manhattan Beach, and Fair Valley in Covina. Although, as a child, he was trained as a classical Pianist, he eventually moved to the guitar. Duval is of mixed ancestry; his mother, a native of Saigon, is of Vietnamese-French descent, and his father is of Irish-Native American-French ancestry. Duval is an avid practitioner of hatha yoga. He also teaches yoga at Earth's Power Yoga studio, Los Angeles, in between films.