With United's junior ranks in the early 1970s, Mitchell made his debut against Manchester City in February 1977, having already appeared in the Anglo-Scottish Cup. He went on to play on 73 occasions for the Magpies. As a teenager, Mitchell was all set to start a new job at a local Sunderland shipyard before United handed him a full-time chance at St. James' Park. Originally a centre-half, then an out-and-out striker, Kenny was converted firstly into a useful utility player, then a competent left-back and later back to a central defender. Always eager to move forward and have a crack at goal, Mitchell was a regular choice in season 1978-79 and had a good run in Arthur Cox's Magpies line-up during 1980-81. He headed to Darlington in August 1981 and later, when he left England in 1984 to join up with top Finnish club Kuuysi Lahti, the Wearsider appeared in European competition and helped lift the local championship. Tall and fair-haired, he won a FA Sunday Cup medal appearing for Wearsiders Humbledon & Plains Farm in the final at St. James' Park during 1988. The club extends its condolences to Kenny's family and friends.​