Howlett made his first-class debut at the age of 18 for Auckland in the National Provincial Chamionhip.

He played with three Super Rugby teams, briefly with the Highlanders and the Hurricanes and, for the majority of his career in his home city, the Blues.

It was with his hometown Blues that he established himself as one of the finest back players in the world, winning a Super 12 title in 2003 Throughout his domestic career, he remained affiliated with Auckland in the NPC with more than 50 appearances for the union.

After becoming the All Blacks record try scorer he left New Zealand rugby after the 2007 Rugby World Cup, taking up a contract with Munster.