Shandi was born to a Huguenot family as Shandra Sinnamon in Miami, Florida.
While she was singing in a local restaurant, a disc jockey noticed her talent and introduced her to Elektra/Asylum Records.
Shandi and Ronald Magness wrote and performed the song "He's a Dream" that was used in the 1983 film Flashdance, the soundtrack of which won the Grammy Award for Best Album of Original Score in 1984.
In 1985, her song "Making It" (composed by Richie Zito) became a local hit in Japan.
(See also Sailor Moon soundtracks (USA)) She has worked as a backing vocalist for Todd Rundgren, Bernadette Peters, Hoyt Axton, and Johnny Hallyday.