Both Ken and his brother Johnny (who was also a professional wrestler)[6] started amateur wrestling while in high school in California, before moving to Texas.
On December 19, 1973, Mantell faced six time and then-current NWA World Junior Heavyweight Champion Danny Hodge in Jackson, Mississippi.
He feuded with wrestlers including Skandar Akbar in Kansas, Don Fargo in Utah, Bob Orton Jr in Fort Worth and Jack Lanza in Dallas.
[4] Towards the end of his in-ring career, Mantell began to transition to a backstage role, working as a booker and valued "brainstormer" in the territory he was perhaps most famous for wrestling with; World Class out of Dallas and Fort Worth.
Mantell was successful and many former WCCW wrestlers would soon join the UWF, including the Fabulous Freebirds, Chris Adams, Missy Hyatt, Skandor Akbar, the Missing Link, Kamala and the One Man Gang.
By the later half of 1986, the 1980s oil glut had hit Texas hard with many job losses in the WCCW markets of Dallas and Fort Worth, resulting in declining attendance at World Class events.
[12] A serious accident to WCCW's top star Kerry Von Erich kept him out of action for a year and a half, which effectively lead to World Class's major decline, only a few months out from still being a highly successful territory[13] It wasn't long before the oil recession hit Bill Watts in Oklahoma and he eventually sold the UWF to Jim Crockett in 1987.
His brother "Cowboy" Johnny Mantell is the current president of the Professional Wrestling Hall of Fame and Museum in its new location of Wichita Falls, Texas.