Gareth became the first Scottish player to be selected for two Commonwealth Games in Basketball as the only returning member of the Melbourne 2006 team. At the 2018 Gold Coast Games, Gareth helped the Team Scotland reach the bronze medal match, finishing the Games in 4th. At Birmingham 2022 Commonwealth Games he was apart of the team that got a 4th place finish after a tight 13-12 loss to Canada.
Gareth was called-up at cadet level in 2002 to represent Scotland, and captained the national side at the 2012 European Championships. He has also represented Great Britain at EuroBasket 2017 and the 2019 World Cup Qualifiers.
After returning to the club in 2016, Gareth is now in his 4 consecutive season playing for the Glasgow Rocks, who are Scotlands only professional basketball team playing in the British Basketball League. The 2019-20 season saw Gareth become the Rocks team captain. He is also the Director of the Glasgow Rocks Basketball Academy.