In August 2005, Casey "The Underdog" Olson began his MMA career in Lemoore, CA at WEC 16. Casey Olson went undefeated in his first 4 fights under the WEC banner, before going off to fight for Strikeforce. Olson returned to the Tachi Palace Hotel and Casino to fight for Palace Fighting Championship (PFC) – which took over for the WEC after they were acquired by the UFC. Eventually the PFC gave way to Tachi Palace Fights. Now, after a near-2-year layoff, Casey Olson is 2-0 in Tachi Palace Fights thanks to a unanimous decision victory over Cody "The Renegade" Gibson in the TPF 12 main event.