In 2004, Munn interned at Fox Sports Networks and worked as a sideline reporter for college football and women's basketball.
She has gone on to say that she disliked the experience, explaining, "I was trying to be something I wasn't, and that made me really uncomfortable on live TV." Soon after she moved to Los Angeles, Munn was cast in a small role in the direct-to-video horror film Scarecrow Gone Wild.
In 2011, Munn appeared in the comedy film I Don't Know How She Does It (2011) as Momo.
In 2012, Munn had a leading role in The Babymakers, a minor role in Freeloaders, and appeared in Magic Mike, directed by Steven Soderbergh.
The half-hour romantic comedy premiered on 20 January 2011.
Munn also appeared in the July/August 2007 issue of Men's Health.The films aired on Direc TV and In Demand pay-per-view.In late 2005, Munn began her role as teen surfer Mily Acuna over two seasons of the television drama Beyond the Break on The N network. The network, devoted to the world of video games and the video game lifestyle, was at first hesitant to hire Munn.Munn began her professional career in television journalism before becoming an actress.
In 2006, Munn starred as Mily Acuna on the series Beyond the Break. from 2006 to 2010 and was a correspondent on The Daily Show from 2010 to 2011.Munn had a significant role in the horror film Insanitarium in which she played a nurse at an insane asylum.