Educated at Taverham High School, as a teenager she was spotted recording Stevie Wonder-influenced demos at The Kitchen in Norwich with her father (himself an experienced musician and local restaurateur) on piano. At the time she was working for Norwich Union. Simon Fuller signed her to his 19 Management company and to label Polydor at aged 17, and this began a career-long association with the impresario that has seen Dennis provide songs for many Fuller-related artists and projects.
Dennis achieved her first success as a vocalist with D Mob, when their single "C'mon and Get My Love" reached #15 in the UK Singles Chart and #10 in the Billboard Hot 100 in 1989. It is regarded as an underground classic in the dance music field, and a second collaboration with D Mob, "That's the Way of the World", was also a hit. It was followed by Dennis' debut album, Move to This. She subsequently scored three solo hits, all of which reached the UK Top 20 and the US Top 10. She enjoyed considerable success in Japan in the early 1990s. The three solo hits were: "Just Another Dream" (UK #13, US #9, Australia #14), which featured D Mob on backing vocals; a cover of the Wish (featuring Fonda Rae) 1984 club hit "Touch Me (All Night Long)" (UK #5, US #2, Australia #16), which is probably her most remembered hit to date; and "Too Many Walls" (UK #17, US #8, Australia #57).
Subsequent releases were only minor hits. Her final Top 40 hit in the US was "You Lied to Me" in 1992, taken from her second album Into the Skyline, and her final Top 40 hit in the UK was a cover of the Kinks' classic "Waterloo Sunset", which made #11 during 1997. That same year, her last solo single, "When Your Dreams Turn to Dust", peaked in the UK at #43. These two latter singles were both taken from her third and last solo album, Am I the Kinda Girl?, also including a third single, "West End Pad", the album opening track (UK #25).
"Touch Me (All Night Long)" stayed at #2 on the Billboard Hot 100 for two weeks, and was kept out of the #1 spot by Hi-Five's "I Like The Way (The Kissing Game)" in the first week, and Mariah Carey's "I Don't Wanna Cry" in the second week. The song was a cover and lyrical reworking of a 1984 single by Wish featuring Fonda Rae, which had hit #70 on the US R&B chart that year. "Touch Me (All Night Long)" reached #1 on the US Hot Dance Club Play chart, and its follow-up, "Too Many Walls", which Dennis co-wrote with Anne Dudley of Art of Noise (who also co-wrote the ABC track "All of My Heart"), was a #1 Adult Contemporary hit in the United States. It was around this time Dennis agreed to join Club MTV's first tour, booked for six weeks. She dropped out on the third date, later publicly accusing one of Milli Vanilli's members (the tour's headline act) of sexual harassment. During this period, she recorded a song called "Find the Key to Your Life" with David Morales, for the soundtrack to the movie Teenage Mutant Ninja Turtles II: The Secret of the Ooze.
Dennis released her second album, Into the Skyline, in May 1992, written with an aim toward the US market. The album featured the singles "You Lied to Me", "Irresistible", "Moments of Love," "Falling", and "Why" – the latter was credited to D Mob with Dennis. The album got to #8 in the UK Album Chart, whilst in the US Billboard Hot 100, "You Lied to Me" was a Top 40 hit, and "Irresistible" made the Adult Contemporary Top Ten; however, the album descended the chart rapidly. Dennis experienced a brief peak of fame, making a cameo in Beverly Hills, 90210 singing the songs "Moments of Love" (a minor US Adult Contemporary chart hit), "Why" (in the episode, without D Mob) and "Touch Me (All Night Long)". In Japan, the album was called Into the Skyline +1, and featured three extra tracks: "Nothing Moves Me", a previous B-side, and two tracks that were both released as singles, "It's My Style", and "Love's a Cradle". She also provided background vocals on PM Dawn's American Top Ten and British Top Twenty hit "Looking through Patient Eyes", released in 1993.
Dennis began to record a third album, Inspiration. The title track was recorded with Todd Terry, along with another song "Is There Life After You". Only one song from the recording sessions was ever released, "S.O.S.", which can be found on the Beverly Hills 90210: The College Years soundtrack. She wrote her first song for another artist by writing a song for Dannii Minogue called "Love's on Every Corner".
In 1996, Dennis changed musical tack: away from the dance-pop sound of previous releases, to a more traditional singer-songwriter approach. The resulting album, Am I the Kinda Girl?, was more in keeping with the Britpop sound of bands such as Blur and performers such as Stephen Duffy, and featured collaborations with Guy Chambers of The Lemon Trees and Andy Partridge of XTC.
In 2001, Kylie Minogue had a worldwide hit with the Dennis and Rob Davis penned song "Can't Get You Out of My Head". The following year Dennis won the Best Dance Recording Grammy for writing "Come into My World". She followed that up with Britney Spears's hit song "Toxic" which also won the Grammy for Best Dance Recording. Dennis had a string of hits with S Club 7; she wrote almost all their hit singles, and also worked on the singles for the spin-off group S Club 8 which was a younger version of S Club 7. Dennis wrote hit songs for Céline Dion, Australian siren Delta Goodrem, and for Hear’Say and Bardot. She also wrote the fastest selling debut single in UK history for recording artist Will Young, the winner of the British show Pop Idol, and his runner-up Gareth Gates. Dennis wrote the theme song to the television series American Idol. She also wrote several songs for former S Club 7 member Rachel Stevens and also two songs for Phil Roy, one of which was on the soundtrack for As Good as It Gets starring Jack Nicholson and Helen Hunt.
According to news reports, Dennis was working on a new album under the name Sexcassettes, which she planned to release in 2008. She has collaborated with Mark Ronson on his album, The Business.
In 2015, Cathy Dennis collaborated with Galantis by performing, uncredited, on "Runaway (U & I)" and "Louder, Harder, Better", both from the album Pharmacy.
Dennis has achieved critical and commercial success as a songwriter, winning a number of award-winning songs and penning many international hit singles. Her first mainstream success was with "Bumper to Bumper", the B-side to the Spice Girls' hit "Wannabe". Dennis continued this success by co-writing the Pop Idol theme (re-used for numerous international remakes of the show, including American Idol), and writing for Idol contestants, including Kelly Clarkson, Will Young, Gareth Gates, and Clay Aiken. Clarkson's single "Before Your Love" (a double a-side with "A Moment Like This") was Dennis' first US No. 1.. Dennis' "Can't Get You Out of My Head" (recorded by Kylie Minogue) spent four weeks at number one in Britain, while also rekindling interest in Minogue in America, where it hit #7 on the Billboard Hot 100). With over three million copies sold worldwide, Can't Get You Out of My Head" became the second highest selling single in 2001. In 2005, Dennis won her first Grammy for co-writing Britney Spears' single "Toxic". Dennis' biggest success came in 2008 with Katy Perry's smash hit "I Kissed a Girl", which ranks among the best-selling digital singles in history. Most recently, Cathy co-wrote 3 tracks on the Galantis album Pharmacy, one of which, "Runaway (U & I)" reached No. 1 in the UK Dance chart, No. 9 in the US Dance chart, and was nominated for a Grammy.Move to This (1990)
Into the Skyline (1993)
Am I the Kinda Girl? (1997)