Jeff was born in Midland, Texas on June 2, 1956 to Alvis and Maxie Sewalt. He married Taronna Chambers on November 1, 1975, in Rising Star, Texas. She preceded him in death on July 28, 2006.
He was a member of the Cowboy Church of Erath County. He was also a champion team roper, and a member of all the Team Roping Associations.
Survivors include his mother, Maxie Brown Sewalt; daughter, JeTonna Gilliam, and husband Ky, of Early; Son, Judd Sewalt of Weatherford; his two sisters, Bonnie Burrus, and husband William, of Stephenville, and Teddi Morrow of Lampasas; brother, Alvis (Sambo) Sewalt, and wife Tawnya, of Athens; and two grandchildren, Vegas Gilliam and Harley Gilliam. He also had several nieces and nephews. He was preceded in death by his father Alvis Lynn Sewalt.