Nicknamed "Joffa", his younger brother, Tom Simpkin was also a professional Australian rules footballer who played for St Kilda.

Simpkin spend the 2006 and 2007 season playing for the Sydney Swans reserves team that won the 2006 and 2007 AFL Canberra premierships.

[5] He continued to play for Geelong in the VFL and despite performing well consistently throughout the season, winning the team's best and fairest award,[6] he was unable to break into the AFL side.

Owing to injury to Brendan Whitecross he was selected for Hawthorn's grand final team and was subbed on at three quarter time winning a premiership medal when the Hawks defeated Fremantle, in his first season at the club.

He also played in Box Hill's VFL premiership team winning the Norm Goss Memorial Medal for his best on ground performance that day.