From 2009 to 2011, Griffin played for the Melbourne Storm's NYC team, scoring 13 tries in 46 appearances, before graduating to the Storm's New South Wales Cup team, Cronulla-Sutherland Sharks in 2012. In a 2012 pre-season trial match, he tore the anterior cruciate ligament in his right knee, ruling him out for the rest of the season, however the Storm decided to extend his contract for another year allowing him to come back from injury.
2013
In round 1 of the 2013 NRL season, Griffin made his NRL debut for the Storm against the St. George Illawarra Dragons. In June, he re-signed with the Storm on a 1-year contract until the end of 2014. He went on to play 11 NRL games in his debut season.
2014
In March, Griffin re-signed with the Storm on a 2-year contract until the end of 2016. In April during a New South WalesCup game, he tore his anterior cruciate ligament for a second time, this time in his left knee, stopping him from playing any NRL games in the 2014 season. In July, he received a two match suspension from the NRL after being found to have placed a bet on NRL matches.
After 1056 days since his last NRL match, Griffin returned to the Storm line-up in round 15 of the 2016 season, starting at hooker. In October, he re-signed with the Storm on a 1-year contract until the end of 2017.
2017
In 2017, Griffin was able to break into Melbourne's line-up more regularly, coming off the interchange bench in their 2017 NRL Grand Final win over the North Queensland Cowboys. He finished the season having played in 14 NRL matches. Two days after the grand final, he signed a 2-year contract with the Newcastle Knights starting in 2018, in a bid for more first-grade opportunity with AustraliancaptainCameron Smith ahead of him for the starting position at the Storm.
2018
In round 1 of the 2018 season, Griffin made his debut for the Knights in their 19-18 golden point extra-time win over the Manly Warringah Sea Eagles, scoring a try. In June, he made his international debut for New Zealand against England in Denver, Colorado. Just a week later, while playing for the Knights in their round 16 clash against the Canterbury-Bankstown Bulldogs, he was passing the ball from dummy half and his leg got caught in a position which ruptured multiple ligaments in his left knee, including a ruptured anterior cruciate ligament knee graft, ruptured lateral ligament and torn lateral meniscus. This would be his third ACL knee injury to his left knee and meant he faced a 9-12 month recovery period.
2019
While working as a trainer and coach for the Knights during the 2019 season, Griffin ultimately didn't make it back from his knee injury, departing the club at the end of the season.
Coaching career
In July 2020, Griffin was announced as the new coach of the New Zealand Warriors NRL Women's team.