Mitchell, a product of the Southland academy system, made his debut for the Stags during the 2009 Air New Zealand Cup, and served as backup to Jason Rutledge after David Hall suffered a season-ending knee injury.
A serious neck injury forced Mitchell to miss the entire 2018 Mitre 10 Cup season.
Mitchell was selected to the Highlanders squad for the 2011 Super Rugby season, where he served as the team's 3rd choice hooker behind Jason Rutledge and Mahonri Schwalger and made 4 substitute appearances.
He continued as the Highlanders 3rd choice hooker through 2014 before transferring to the Hurricanes for 2015, where he was a squad regular making 11 substitute appearances.
Mitchell was a member of the 2009 New Zealand Under 20's who won the IRB Junior World Championship, and scored a try in the final against England after a brilliant pass from Stags teammate Alex Ryan.