Prowse met Frank Sinatra on the set of Can-Can. Time magazine did not rate the movie highly, but declared Prowse the best thing in it: "In fact, the only thing really worth seeing is Juliet Prowse, a young South African hoofer who puts some twinkle in the stub-toed choreography. And the only thing really worth hearing is the crack that Frank flips back at Juliet when she whips a redoubtable hip in his direction. "Don't point", he gasps. "It's rude." She would go on to appear with Sinatra and other notable guests such as Ella Fitzgerald, Peter Lawford, Hermione Gingold, the Hi-Lo's, Red Norvo, Nelson Riddle and his orchestra on the 1959 Frank Sinatra Show. She at times would sing in the chorus with other guests or Sinatra would sing to her.

Prowse was born in Bombay, British India to South African parents and reared in South Africa. She began studying dance at the age of four. In her early twenties, she was dancing at a club in Paris when she was spotted by a talent agent and eventually signed to play the role of "Claudine" in the Walter Lang film Can-Can (1960). She had already missed a few opportunities to go to Hollywood because she was under contract but eventually left a show in Spain in which she was starring to travel to the United States for this film.

Prowse also did other feature films, including The Fiercest Heart (1961) and Who Killed Teddy Bear? (1965) with Sal Mineo and Elaine Stritch.

Sinatra invited Prowse to join him in Las Vegas, even though she was living with the actor Nico Minardos at the time. Sinatra and Prowse announced their engagement in 1962. Soon afterwards they broke up, reportedly because Prowse wanted to concentrate on her career. Prowse later admitted, "I was as much flattered as I was in love. He (Sinatra) was a complex person, and after a few drinks he could be very difficult."

Prowse co-starred alongside Elvis Presley in G.I. Blues (1960). During shooting of the film, they had a short and intense fling. "Elvis and I had an affair. ... We had a sexual attraction like two healthy young people, but he was already a victim of his fans. We always met in his room and never went out." Prowse also made a brief cameo appearance in the Metro-Goldwyn-Mayer documentary film, Elvis: That's the Way It Is (1970) as an interviewed audience member about to attend Elvis Presley's opening night show at the International Hotel in Las Vegas, Nevada on August 10, 1970.

Throughout the mid-1980s and 1990s, Prowse hosted the Championship Ballroom Dance Competition on PBS.

In 1994, Prowse was diagnosed with pancreatic cancer. In 1995, she went into remission and was well enough to tour with Mickey Rooney in Sugar Babies. The cancer subsequently returned and she died on September 14, 1996, eleven days short of her 60th birthday.

She starred with Denny Scott Miller on her own NBC sitcom in the 1965-1966 season: Mona McCluskey, which was produced by George Burns. The series was based on the idea that the couple, Mike and Mona McCluskey, would live on his military salary, rather than her lucrative earnings as an Actress. Miller died on September 9, 2014.