Aguilera performed "Fighter" on a number of shows. The singer performed the song for the first time on Saturday Night Live on March 15, 2003. Aguilera also performed "Fighter" at the 2003 MTV Video Music Awards, held at Radio City Music Hall in New York City on August 28, 2003, in a medley with "Dirrty".; the performance featured Redman as a featured artist, and Dave Navarro as the guitarist. There, she also performed with Madonna, Britney Spears and Missy Elliott a medley of Madonna's songs "Like a Virgin" and "Hollywood", and Elliott's "Work It". The song was also performed on Aguilera and Justin Timberlake's 2003 summer tour Justified and Stripped Tour, in order to support Stripped and Timberlake's album Justified. In late 2003, Aguilera performed the track during the tour's extension, The Stripped Tour, which happened without Timberlake. The performance is included on her first full-length DVD Stripped Live in the U.K. (2004). On June 1, 2007, during the promotion of Back to Basics, Aguilera performed "Fighter" along with "Ain't No Other Man", "Hurt" and "Candyman" at the 2007 Muz-TV Awards. Later, during her 2006–07 Back to Basics Tour, the track was performed as the last song in the encore. Barry Walters for Rolling Stone labelled the performance of "Fighter" "ended the show on a hard-rocking high". It is included on the video release Back to Basics: Live and Down Under (2008).
On June 8, 2010, the singer sang the track with four other songs, "Bionic", "Not Myself Tonight", "Beautiful" and "You Lost Me" on The Today Show. Selected as the opener of the show, James Dinh for MTV News named it "aggressive", while Erika Brooks Adickman for Idolator called the performance a "hot-mess show wardrobe". On June 11, 2010, Aguilera performed "Fighter", "You Lost Me", "Not Myself Tonight" along with a medley of "Genie in a Bottle" and "What a Girl Wants" on The Early Show. Later that year, on June 13, she performed all of her biggest hits on VH1 Storytellers, including "Fighter". Before performing the song, Aguilera revealed to the crowd, "When I was younger there were a lot of people, as I mentioned before, that were sort of around me for the wrong reasons. There's always a positive to those negative times because throughout it you come out so much stronger and wiser". During the Justin Timberlake & Friends benefit show–held by Justin Timberlake on October 24, 2010, in Las Vegas, Nevada–Aguilera was invited to perform several of her hits, including "Beautiful", "Fighter" and "Ain't No Other Man". On April 16, 2012, Aguilera performed "Fighter" again on the second season of US reality show The Voice, on which she is one of the judges and coaches, with her "Team Xtina" and Crenshaw High School choir. Jonathan Hofmann called the performance "insane and bizarre as it sounds".
In July 2021, Aguilera performed the song for two nights at the Hollywood Bowl with Gustavo Dudamel and the Los Angeles Philharmonic. She also sang excerpts from the song during the 47th People's Choice Awards.