Born in Coxhoe, Mitchell began his football career with nearby Northern League side Ferryhill Athletic before joining rivals Crook Town.
Crook won the Northern League in 1926–27, but came under investigation by the Durham County Football Association for illegal payments to amateur players.
In the wake of the investigation, Mitchell left the club for Football League First Division side Sunderland in December 1927.
Although they were the league's top scorers, Darlington finished 13 points behind second-placed Stockport County in third, and missed out on promotion to the Second Division.
[3] In April 1932, Mitchell joined Second Division side Manchester United for £600, but only made one appearance – at outside right against his former club, Notts County, on 18 March 1933 – before being placed on the transfer list.