He most notably had a 17 bout stint in the Ultimate Fighting Championship and competed for the Quad Cities Silverbacks of the IFL where he held an undefeated 9–0 record before leaving the promotion due to a contract dispute.
The young Rothwell, who struggled with his weight and identity in his adolescent years, was also troubled growing up and was often involved in fighting and violence at Westosha Central High School.
By the time he was a junior in high school, Rothwell knew that he enjoyed fighting, and in 1999, at the age of 17, he began learning self-defense.
In July of that same year, after he had been in three professional fights, he and a friend were involved in a car accident with a drunk driver.
Rothwell made his professional debut in early 2001 in his home state of Wisconsin and dominated his opponent, winning by TKO only 21 seconds into the fight.
Rothwell then faced future two-time UFC Heavyweight Champion and fellow Miletich Fighting Systems fighter, Tim Sylvia.
However, he bounced back and won his next seven fights, all by submission or TKO, before a unanimous decision loss to Mike Whitehead.
On April 29, 2006, Rothwell made his IFL debut against future UFC veteran, the Polish-Canadian fighter, Krzysztof Soszynski.
Despite the round ending, referee Dan Miragliotta called a stop to the contest, granting Rothwell the win via TKO.
His next fight was a rematch from almost five years earlier against veteran Travis Fulton, owner of 195 career victories.
However, the Silverbacks fell short of a victory and lost the championship to Renzo Gracie's New York Pitbulls.
[7] After the fight, UFC president Dana White stated that Mazzagatti was the "worst referee in the history of combat sports".
[8] However, Rothwell had to withdraw from the event, just days prior, due to an illness and was replaced by Anthony Perosh.
[14] Rothwell was expected to face Travis Browne at UFC on Fox: Shogun vs. Vera, but pulled out due to an injury[15] Rothwell faced Gabriel Gonzaga on January 19, 2013, at UFC on FX: Belfort vs. Bisping[16] He lost the fight via submission in the second round.
[26] Subsequently, Rothwell was removed from the card the following day after the promotion deemed that a suitable opponent could not be arranged on short notice.
[33] However, Rothwell pulled out of the fight on August 11 citing a knee injury and was replaced by Travis Browne.
[37] Having served his suspension, Rothwell returned to face Blagoy Ivanov on March 9, 2019, at UFC Fight Night 146.
[43] The finish was controversial as Rothwell had accidentally hit Struve in the groin twice and was docked one point for these infractions in the second round.
The referee encouraged the compromised Struve to continue, resulting in a finish for Rothwell late in the second round.
[46] Rothwell faced Ovince Saint Preux at UFC Fight Night: Smith vs. Teixeira on May 13, 2020.
[53] While Rothwell made weight without issue, Lins never showed up to the weigh-ins and withdrew from the bout due to an illness.
[59] Rothwell faced Marcos Rogério de Lima on November 13, 2021, at UFC Fight Night 197.
[67] Rothwell won the fight by technical knockout after Duffee was knocked down and injured in the first round.
They often compete as a team at Wisconsin Xtreme Cage Fighting (WXCF) events at Racine Memorial Hall.