Brierfield, Lancashire born right half or centre half James Mitton began his football career on the books of local Second Division club Glossop, where he spent 1909-10 without breaking into their first eleven. After a brief spell with Lancashire Combination club Darwen he signed for Second Division club Stockport County, for whom he made his Football League debut against Birmingham in February 1911. On the fringes during his first two seasons at Edgeley Park, he broke into The Hatters’ first eleven in November 1913 and was a regular in their first team until the onset of the First World War forced the suspension of peacetime football in May 1915.
After the War he returned to Stockport County and was a regular in their first post war season, but he then lost his place in October 1920 and signed for Exeter City, where his brother was already playing, shortly before the start of the 1921-22 season after 6 goals in 90 appearances for The Hatters. Mitton missed only two matches in his debut season with The Grecians and stayed another season, then returning to his native Lancashire, moving on to play for Nelson. However, he failed to make an appearance during his single season with the Seedhill club, and he retired from professional football in the summer of 1924.
His brother Jack Mitton was also a footballer and the two brothers briefly played together at Exeter City, Jack also played for Sunderland, Wolverhampton Wanderers and Southampton.