Campbell decided to use the name “Little Nell” as a stage name after her arrival in Britain in the early 1970s with her family. She sold clothes at Kensington Market; her stall was next to Freddie Mercury’s. She also worked as a busker and as a soda jerk in a café, where her tap dancing is often noted as the reason why she was cast as Columbia in the original production of The Rocky Horror Show following an impromptu audition. She reprised the role in The Rocky Horror Picture Show, released in 1975, and starred as Nurse Ansalong in the 1981 sequel, Shock Treatment.
After The Rocky Horror Picture Show, Campbell signed a recording contract with A&M Records. Her debut single was “Stilettos and Lipstick” backed with “Do the Swim”, released in 1975. She also recorded a disco version of the song “Fever” in 1976, which was again backed with “Do the Swim”. The B-side of both of these releases became better-known, perhaps helped by a performance on British television in which she accidentally (and repeatedly) exposed her breasts. While edited out of the original broadcast in 1975, the unedited version was shown worldwide on bloopers shows (beginning with the British show It’ll be Alright on the Night in 1977). Following this notoriety, another effort was made to promote the recordings made in 1975 and 1976. In 1978, a “triple B-side” extended play titled The Musical World of Little Nell (Aquatic Teenage Sex & Squalor) was released which featured both “Do the Swim” and “Stillettos and Lipstick” along with the track “Dance that Cocktail Latin Way” (also known as “Tropical Isle”) which originally appeared as the B-side of her second single from 1976. Following some success with the EP, the other two tracks, singles “Fever” and “See You Round like a Record”, were released as a single but that was to be her last release on A&M. A final single, “Beauty Queen” from the film The Alternative Miss World, was released on PRE Records in 1980.
Campbell has also appeared in several stage productions, including the Off-Broadway play You Should Be So Lucky and the Broadway musical Nine. She appeared as Sandra LeMon in the British TV series Rock Follies of ’77.
In 1986, Campbell opened the nightclub Nell’s on West 14th Street in Manhattan (New York) with Keith McNallyand Lynn Wagenknecht. In 1995 she opened two restaurants in New York: The Kiosk (uptown) and E&O (downtown).
Campbell has written several magazine articles, including regular segments called “MamaTalks” and “First Look” in the now defunct Talk magazine, starting in the December 1999 issue.