She competed on the second series of the televised singing competition The X Factor in 2005 as a member of the girl group Addictiv Ladies. In 2012, she then launched a solo career with the record label Strictly Rhythm and released songs with dance musicians including DJ Fresh and Drumsound & Bassline Smith. East returned to The X Factor as a solo artist in 2014 for its eleventh series, where she finished in second place behind Ben Haenow.
Fleur East signed to the record label Strictly Rhythm in January 2012 and released two singles as the lead artist (credited as Fleur): "Broken Mirror" with Cutline and "Turn the Lights On" (produced by Culture Shock). She also featured on "The One" by Horx and P3000. In 2013, she featured on Drumsound & Bassline Smith's "One in a Million", which entered the UK Singles Chart at number 53, and headlined the Miss Face of Africa EU ceremony in London. In December 2013, she self-released her debut EP She for free download. One of the EP tracks, "Super Rich Royals", is a mashup cover of "Super Rich Kids" by Frank Ocean and "Royals" by Lorde.
Fleur East worked as a waitress at the London nightclub Aura Mayfair to help support her music career, and was also a fitness model with the agency W Athletic.
In June 2014, East auditioned for the eleventh series of The X Factor. She sang John Legend's "Ordinary People" in her room audition, where she received three "yes" votes and progressed through to the arena auditions. She sang Chris Brown's "Fine China" at the arena and progressed to the boot camp stage with four "yes" votes. East made it past the six chair challenge and through to the judges' houses stage in the "Over 26s" category, mentored by Cowell once again, to whom she performed "Bang Bang" by Jessie J, Ariana Grande and Nicki Minaj. Cowell chose East for the live shows, alongside Jay James and eventual winner Ben Haenow.
In the semi-final of the live shows, East performed "Uptown Funk" by Mark Ronson featuring Bruno Mars.
East's version went to number one on the UK iTunes Store, which led the original song to be released five weeks earlier than planned; it subsequently reached number one on the UK Singles Chart. In the final, the show's final, East was announced as the runner-up in the competition, losing to fellow category act, Ben Haenow with 34.3% of the votes to Haenow's 57.2%