[citation needed] He was first alerted to AFL scouts in the 2005 MacRory Cup final, at which the Australian U17 international rules football team was present.
In October 2007, when Clarke returned home from Australia for a three-week holiday and during that time helped his local club An Ríocht GAC lift its first ever Down Division One league title, defeating Kilcoo in the final.
[2] Clarke was developed through Collingwood's VFL affiliate the Williamstown Football Club, where he played a number of games semi-professionally as a rookie before debuting at AFL level.
In another promising display, Clarke picked up nineteen possessions and three goals, playing on former brownlow medallist Shane Crawford in a sell out crowd in front of 50,248 at Melbourne's Docklands Stadium.
[6] Clarke announced his retirement from AFL on 24 September 2009, citing his desire to return home and to play Gaelic football, which he said had prompted him to decline the offer of another three-year contract in Australia and that "I could easily have stayed.
His poor form in the early stages improved as Down reached the Ulster championship semi-final and recovered from defeat in this game to successfully make their way through the qualifiers.
In the All-Ireland Senior Football Championship quarter-finals they recorded a surprise win over Kerry before narrowly overcoming Kildare in the semi-finals setting up and All Ireland final meeting with Cork Downs first since 1994.
Clarke opted not to play in the International Rules Series between Ireland and Australia, instead completing the start of preseason training with his new team.