Before her acting career, Simone served in the United States Air Force as an engineering assistant. Afterwards, she sang background for various European artists and was part of the Spanish artist Raphael's touring chorus.
Simone's stage debut was in a national tour of the Andrew Lloyd Webber rock musical Jesus Christ Superstar, as Soul Sister and understudy for Mary. In 1996, she continued her career as a swing and female understudy in the original Broadway production of Rent. Later that year, Simone performed the lead role of Mimi Marquez in its first national tour, from November 1996 to April 1998.
Starting in 1998 Simone took a hiatus from acting during which she toured and recorded two albums with the acid jazz band Liquid Soul. Along with the rest of the band, she was nominated for a Grammy Award for their 2000 album Here's the Deal. Simone then returned to the Broadway stage in the title role of the Disney musical Aida. She performed the role from January 29, 2002, until June 15, 2003. She reprised this role for a short time at The Muny Theater in St. Louis in the summer of 2006. In the summer of 2007, she played Fantine in Les Misérables at The Muny.
Simone has released three solo albums: Simone Superstar, Simone on Simone and All Is Well.
She tours frequently, singing jazz standards and her own material, most recently on tour in Europe with her 2014 album All Is Well.
Simone is the daughter of Nina Simone and Andrew Stroud. She is married to Robert Kelly, with whom she has a daughter named ReAnna Simone Kelly. Both Simone and her daughter have appeared on Psychic Kids (Season 1 Episode 4), the Larry King Show, and the Tyra Banks Show.