Polwart attended Sacred Heart College in Auckland and during that time was a NZ secondary schools Barbarians representative, he also went on to captain Auckland at under-19 level before moving to the Bay of Plenty along with New Zealand under-20 team-mates Mitchell Karpik and Henry Stowers in late 2015.
Polwart made his senior debut for the Bay of Plenty Steamers during the 2016 Mitre 10 Cup season and went on to make 6 appearances before injury curtailed his campaign.
Despite having only made 6 senior appearances, Polwart was named in the Chiefs squad ahead of the 2017 Super Rugby season, where he would compete with All Blacks Hika Elliot and Nathan Harris for the number 2 shirt.
Polwart made 5 appearances for the Chiefs in Super Rugby and made an additional appearance against the British and Irish Lions.
He also represented the Maori All Blacks in November to cap off a fantastic year for the youngster.
JW December 17
|Bay of Plenty
|2016 - present|
|New Zealand U20's
|2015 - 2015|
|Maori All Blacks
|2017 - 2018|
|2017 - 2019|