McKnight began her career when she was seventeen at 2005 at Disney Channel's TV Movie Go Figure.

In 2007, she starred in the film Whisper Island, in which she played the role of Sam Dalton.

She is also known for her roles in the 2008 television series Lifeless and teen romantic comedy HottieBoombaLottie which was picked up by MTV.

In 2009 she played the lead role, serial killer's daughter Skye Rotter, at MTV's My Super Psycho Sweet 16.

In January 2016 McKnight was the lead subject of a New York Times article about Los Angeles based actors and artists taking jobs driving for Uber and Lyft at between acting and artistic jobs.