She is known for her role as Olive Doyle on the Disney Channel series A. She also played Lilith on The CW television series Supernatural.
Farm and her participation on the game show Are You Smarter Than a 5th Grader?
She moved to Los Angeles, California at a young age.
Mc Cormick first took an interest in acting in 2006 when she joined The Corsa Agency in Los Angeles.
Taking place in San Francisco, the series stars China Anne Mc Clain, Sierra Mc Cormick, and Jake Short as middle-schoolers in a gifted program at their local high school called the "Advanced Natural Talent" or "A. The school is run by a big technology company, Z Tech, owned by Zoltan Grundy (Dominic Burgess). Someone who's got all of this natural talent & ability, but is still challenged when she's sent off to high school at the age of 11? Sierra Mc Cormick was cast after an audition where she continually talked about tigers.Jierra (J/ake and S/ierra) is the real life pairing of Jake Short and Sierra Mc Cormick. The pair seem comfortable around each other and even did a "Monkey Kong Country Returns" photoshoot together. This pairing is one of the most popular real-life pairings in A. The series ended with Fletcher (Jake Short) winning an art fellowship in New York City and moving there with his 30 year old grandma. Dan Signer stated "And as I heard her continually talking about tigers, I thought 'That's just how Olive would sound,' because Olive is a fast talking, intelligent student whose talent is memory, which is how Sierra got that part." Jake Short was the last of the three core characters to be cast.The show was first conceived when Dan Signer, creator of the show, saw China Anne Mc Clain. Caroline Sunshine was originally cast as Lexi and Stefanie Scott as the role of Tinka Hessenheffer in Shake It Up!