[citation needed] Born in the Wairarapa, Clarke grew up in Poverty Bay, where he attended Gisborne Boys' High School.
During Clarke's domestic career he has reached the quarter-finals of New Zealand's National Provincial Championship on three occasions, once with Canterbury in the 2006 season, and twice with Taranaki in their 2007 and 2008 campaigns.
[3] He captained the team in one of their greatest ever victories as they beat four time European champions Toulouse away in the Stade Ernest-Wallon, in the Heineken Cup pool stages.
[5] Clarke's first season with Connacht was ended prematurely when he was forced to take a break from the game indefinitely, due to concerns for his health after he suffered his tenth concussion in less than two years in a Heineken Cup match with Saracens on 18 January 2014.
Clarke was involved in the New Zealand under 19 team when they won the Under 19 Rugby World Championship that took place in Italy in 2002, beating the French U19s in the final.
Although Clarke, then aged 26, had played only sixteen matches for the Crusaders and Hurricanes, the Junior All Black coaches selected him as cover for Bryn Evans for the Pacific Nations Cup.