Deschanel was born in Philadelphia, Pennsylvania to a French father and an American mother, who raised him in her Quaker religion. He went to Severn School for high school. He attended Johns Hopkins University from 1962 to 1966, where he met Walter Murch, with whom he staged happenings, including a memorable one in which Murch simply sat down and ate an apple for an audience. Murch graduated a year ahead of him and encouraged Deschanel to follow him to the University of Southern CaliforniaSchool of Cinematic Arts, where he graduated in 1968. During this time, he was a member of a band of film students called The Dirty Dozen, a group that attracted the attention of the Hollywood system. Following his graduation, he attended the AFI Conservatory and graduated with an M.F.A degree in 1969.