Jarre was born on August 6, 1954, in Detroit, Michigan, to actress Laura Devon and her second husband, Cleland B. Clark. After his parents' divorced, he lived in Wyoming for a time with his father, whom he referred to as Hemingwayesque, and who had combined ranching and fashion photography. He then returned to Los Angeleswith his mother, who was married at that time to actor Brian Kelly. In the mid-1960s, Devon subsequently married French composer Maurice Jarre, who adopted Kevin.
He was the step-brother of Jean-Michel Jarreand Stéfanie Jarre.
In the early 1990s, he had dated actress Lisa Zane; he had written the role of Josephine Marcus in Tombstone with her in mind.
On July 25, 2009, Jarre was arrested in Santa Monica for driving while intoxicated, his bail was set at $5,000.