Ross' first notable performance was in the 200 m breaststroke final at the British Gas Swimming Championships 2012 where he achieved a seven-second personal best at the London Aquatics Centre. 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 2014 Ross had international success with Gold in Austin Grand Prix for both the 100 m and 200 m breaststroke as well as taking Gold in the 100 m breaststroke in the Flanders Speedo Cup, receiving the award for top male swimmer due to achieving the highest number of FINA points. In the Scottish National Championships and Commonwealth Trials, Ross picked up two Golds and a Silver medal, achieving a Scottish record in the 100 m of 59.75 which he since improved to 59.56 at the British Championships 2014. 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
In July 2014, Murdoch competed in the 2014 Commonwealth Games which were held in his home city of Glasgow, Scotland. Murdoch qualified for the final of the 200 metre breaststroke with fellow Scots, favourite Michael Jamieson and Calum Tait. He won the Men's 200 metre final, beating Jamieson and Tait at the Tollcross Swimming Centre. This was Murdoch's first major gold medal. On the second day of the 2014 Commonwealth Games, 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. In the final, Murdoch won a Bronze medal with a time of 59.47. Adam Peaty won the race in a Commonwealth Games Record of 58.94, followed closely by Cameron van der Burgh for Silver in 59.28. Ross also qualified for the final of the 50 metre breaststroke, placing 6th in the final.
Personal life
Murdoch started swimming in Alexandria in West Dunbartonshire, close to his hometown of Balloch, when he was 6 years old. He stated his father as being inspirational as he pushed him to achieve success. He was a pupil of Balfron High School. He has a younger sister, Heather, and a younger brother, Scott.