Sidney was born in Los Angeles, CA. She began her training at the Santa Clarita Ballet Academy under the direction of Corinne Glover. Participating in Royal Academy of Dance Exams, she holds her Advanced 2 certificate with distinction. She later graduated magna cum laude from the University of Utah with a BFA in Ballet and a Minor in Human Development and Family Studies. She then joined KCB as a trainee in 2018 before joining the company as an apprentice the following season. During her time with KCB, she has performed in Septime Webre’s The Wizard of Oz, Val Caniparoli’s Lady of the Camellias, Adam Houglands Carmina Burana, and Devon Carney’s The Nutcracker and Swan Lake. This will be Ms. Haefs third season with the main company.