Coming off the back of impressive performances for New Zealand at Under-20 level, Tupou made the Counties Manukau squad for the
2012 ITM Cup. Despite having just turned 20 before the tournament started, he instantly became a regular starter for the Steelers, playing nine times and scoring one try as the men from Pukekohe lifted the Championship trophy and earned promotion to the Premiership for 2013. He continued to excel at Premiership level, playing nine times in
2013,
2014 and
2015 and later being named co-captain for the
2016 season. Being one of the senior players in an inexperienced line up he performed admirably, starting 10 of the Steelers' 11 games during a campaign which took them to the Premiership semi-finals before they succumbed to eventual winners . ==Super Rugby==