 For the 2006 season, Mitchell was named vice-captain of Hawthorn and displayed stellar form throughout the season culminating in winning the Peter Crimmins Medal for Hawthorn's best and fairest.In 2007 he capped off another wonderful season by coming 3rd in the votes for the highest honour in Australian Football, the Brownlow Medal with 21 votes, 1 short of joint 2nd-place winners, North Melbourne's Brent Harvey and Brisbane's Simon Black who both polled 22 votes, and coming 8 votes behind winner of the 2007 Brownlow, Geelong's Jimmy Bartel.On 6 October 2007, during the Peter Crimmins Medal Event, he was announced as Hawthorn's next captain, taking over the reins from retiring captain Richie Vandenberg.