Crahan was born in Des Moines, Iowa. He once performed in bands such as Heads on the Wall, One Cup Fat and Quan. By the early 1990s, Crahan was an alcoholic, which was made worse by his purchase of a local bar in Des Moines, called The Safari. Frustrated by his lack of success, he says he would have turned to suicide had he not met his future wife, Chantel.

As well as lending his percussion talents to the band, Crahan has also sung backing vocals on a number of songs Slipknot has both recorded and performed live. He also wrote the original draft of "Tattered & Torn", which appeared on the band's early demo, Mate. Feed. Kill. Repeat.. Outside Slipknot, Crahan has founded Big Orange Clown Records, a vanity label within Sanctuary Records, which has so far signed the metalcore band Gizmachi. He also acted as director for, and assembled Slipknot's 2006 DVD, Voliminal: Inside the Nine, while the band engaged a brief hiatus.

He also performed with To My Surprise, recording drums and vocals for the band's self-titled debut. The band received little interest due to their album being released amidst the success of Slipknot members Corey Taylor, James Root and Joey Jordison's side projects, Stone Sour and the Murderdolls, respectively. To My Surprise was later dropped by Roadrunner Records. In 2007, Crahan began performing as drummer for Dirty Little Rabbits. The band was a supporting act for Stone Sour during their North American tour in Summer 2007, and have released one EP, titled Breeding. They have since signed a deal with The End Records as of November, 2008. 

Crahan has a wife named Chantel and four children.