McKennon married his childhood sweetheart, Betty Warner, in Portland, Oregon in 1942. The marriage lasted until he died of natural causes on July 14, 2009, five days before his 90th birthday, at the Willapa Harbor Care Center in Raymond, Washington. The couple had six daughters and two sons. They lived in California until 1968, when they moved to Cannon Beach, Oregon, from where Dallas commuted for acting and voiceover roles.