He is considered a pioneer in the sport of MMA and one of the first fighters to use elbows as an effective striking method in the ground and pound position.

Tanner is unusual among MMA-fighters, as he began his professional career with a large degree of success despite primarily learning the sport via instructional videotape.

He worked various jobs around the country as a bouncer, cable television contractor, framer building beach houses, dishwasher, baker, ditch digger, and slaughterhouse worker.

After his initial success, Tanner taught himself submission and grappling techniques using instructional videos created by the famous Gracie family.

Tanner fought once more in Pancrase and defended his title two more times in the USWF before deciding to take the first of multiple breaks from fighting in his career.

He returned in July 2000 and remained undefeated in the USWF, successfully defending his heavyweight belt with wins against Raoul Romero and Vinny Nixon.

He defeated Terrell to become the first UFC middleweight champion since Murilo Bustamante held the title before leaving for PRIDE Fighting Championships in 2002.

With the win, Franklin was named as a coach for The Ultimate Fighter 2 reality television show, along with then UFC Welterweight champion Matt Hughes.

Tanner was ahead on points until the fight was stopped in the second round due to a cut received from a Loiseau elbow.

On December 29, 2006, Tanner unveiled plans to set up a mixed martial arts training camp at his house in Gresham, Oregon for disadvantaged athletes and young men at risk.

In a March 2007 interview with MMA Weekly, Tanner was asked about the possibility of fighting again, but said he wanted to focus on developing his foundation.

On May 11, 2007, further foundation development was put on hold by Tanner, citing his own training and a bad experience with the first fighter that was invited to the house.

He chose to accept no corporate sponsorships and instead started "Team Tanner," an exclusive fan club for his upcoming fights.

In a post-match interview, he said he felt "flat" throughout the fight and that he had begun wondering if his two years of serious alcohol abuse had damaged his body past the point of which he could compete at the level he once had.

"It seems some MMA (Mixed Martial Arts) websites have reported on the story, posting up that I might die out in the desert, or that it might be my greatest opponent yet, etc.

'"[11] He purchased a dirt bike and on September 3, 2008, rode into the desert region west of Palo Verde, California to go camping.

[12] According to his manager, John Hayner, Tanner called that afternoon to say that his bike had run out of gas and that he would walk back to his camp.

Temperatures that day reached 118 °F (48 °C), but in a text message to a friend, he said he thought he could make it back to his camp if he traveled during the later hours of the evening.

A documentary about Tanner's life, travels and philosophy, "Once I Was A Champion," was directed by Gerard Roxburgh[14] and premiered in competition at the 2011 Los Angeles Film Festival as an official selection.

On June 19, 2019, Variety reported that a biopic about Tanner's life and career titled "The Power of 1" was in the works, slated to go into pre-production at the end of 2019 with principal photography planned for early 2020.