She began choreographing on her own with an episode of Tales from the Crypt in 1990, and, when Hornaday was chosen to direct Shout, a John Travolta vehicle, he gave Johnston the nod to choreograph the film on her own—the plot offered the story of a fugitive hired as a music teacher in a Texas town. She also played a lead role of a dancer in the independent comedy, California Casanova (1991 film). Johnston went on to choreograph an episode of Great Scott! on Fox in 1992, as well as the Ray Liotta film, Article 99 that same year. Also a singer as well as a dancer, Johnston was a mere 17 years old when she toured Japan performing and choreographing a stage show. Hornaday has directed her in a music video, "[Here Comes My Baby-1999] ",at the Pink Motel.She has also performed in the 1995 film Showgirls, and, that same year, made a straight comic performance as a Sears salesperson in Grumpier Old Men. In 1999, Johnston performed as a dancer in the Star Trek: Deep Space Nine episode "Badda-Bing Badda-Bang".
She is training the top 21 contestants in an Indian dance show along with the King of Dance in India, Hrithik Roshan. The show is called Just Dance!