[2] Harris was dual registered with Tynedale RFC in National League 1 and also had a loan spell with Rotherham Titans in the Championship.
[3] In October 2014 Harris made his professional debut for the Newcastle Falcons, scoring a try against București Wolves in the European Challenge Cup.
[7] In October 2017, Harris received his first call up to the senior Scotland squad by coach Gregor Townsend for the Autumn Internationals.
He appeared for Scotland in the 2019 Rugby World Cup fixtures and continued his form to play in every match for 2020 Six Nations.
"[12] In 2023 Harris was selected in Scotland's 33 player squad for the 2023 Rugby World Cup in France.