He began his domestic career in his place of birth,
Auckland,
New Zealand and began playing there for the
North Harbour National Provincial Championship team. Simpson then moved to the Wellington side, the
Wellington Lions, in the same competition, while also playing for the
Hurricanes in
Super Rugby. Following his International career, Gordon returned to the North Harbour team, captaining it on a few occasions, one of which being the side's first ever game at its current stadium,
North Harbour Stadium. He then retired from first-class rugby, returning to
North Harbour's premier grade, having played in the grade more than a decade beforehand. ==Scotland domestic career==