Born in Germany to American parents on July 29, 1982 (Age 31), Mack moved to America when she was two years old. Her career in acting began at age four when she worked in commercials advertising German chocolate. Once she turned seven, she started attending The Young Actor's Space in Los Angeles.
After participating in many TV films, Mack's first big break came in 1998 when she portrayed a self-harming teenage girl in the popular TV show 7th Heaven.
In 2001, Mack was casted as Chloe Sullivan in CW's Smallville, one of Clark Kent's best friends. Following that, she appeared in voice overs for The Ant Bully and The Batman. Smallville also paved the way for Mack's directorial career as she directed her first episode in 2008.
Her role as Amanda, the love interest of the main character Ryan Newman, was announced March 2012.