In 2013, Ross made his senior international debut at the World Championships in Barcelona, in which he placed 30th in the 50 m breaststroke in 28.00 and advanced to the semi-finals in the 100 m breaststroke, placing 11th in 1:00.07. Ross was also selected for the British 4×100 m Medley Relay which came 9th in the Championships. In 2015 he claimed the bronze medal in the 100m breaststroke, placing third behind fellow British teammate Adam Peaty and South African Cameron Van Der Burgh with a time of 59.09.
He is currently coached by Ben Higson, although predominantly coached by Jimmy Orr of West Dunbartonshire through his youth and is mentored by Rebecca Adlington Murdoch successfully qualified (coming first) for the final of the 200 metre breaststroke with fellow Scots, favourite Michael Jamieson and Calum Tait.
This was Murdoch"s first major gold medal. On the second day of the 2014, Murdoch qualified as the second fastest swimmer for the 100 metre breaststroke in a time of 59.72.
The fastest qualifier was Adam Peaty in a time of 59.16. Ross also successfully qualified for the final of the 50 metre breaststroke, placing 6th in the final.
Murdoch started swimming in Alexandria in West Dunbartonshire, close to his hometown of Balloch, when he was 6 years old.
He was a pupil of Balfron High School.