Sierra is from Tampa, Florida, and auditioned in Orlando. This girl was also a contestant on Star Search before auditioning for Idol, and was a nanny. She started singing in church at the age of 3. As a teenager, she performed for Presidents Bill Clinton and George W. Bush in singing and dancing ensembles. She first auditioned for Idol in the second season, but was rejected.

Sierra was eliminated on March 30, during 1990s music week, after she sang LeAnn Rimes' "On the Side of Angels", surprising some fans since Simon Cowell had previously stated that she was one of the strongest female vocalists in the competition.

She dated fellow American Idol 4 contestant, Nikko Smith for several months. In an April 2006 article in the Tennessean, Sierra confirmed the relationship but said the two broke up shortly after New Year's.