Mark Dekanich was born on May 10, 1986 in Vancouver, British Columbia. He played his collegiate hockey for Colgate University where he was a ECAC First Team All-Star in 2006 and Second Team All-Star in 2007. Drafted 146th overall by the Nashville Predators at the 2006 NHL Entry Draft, he joined the club's AHL affiliate, the Milwaukee Admirals in 2008.
After two and half successful seasons in the American Hockey League, Dekanich finally got his first taste of NHL action on December 18, 2011, when he came in relief of Predator's starter Anders Lindback.
On July 3, 2011 Dekanich was signed as a free agent by the Columbus Blue Jackets.