[1] He began his football career as an apprentice with Newcastle United,[3] and made his senior debut on 16 February 1977 at home to Manchester City in the First Division.
In stoppage time, "there was the poignant sight of Kenny Mitchell, a 19-year-old making his first appearance, angrily chastising himself for screwing the ball wide from a good position".
[2][9] For the new campaign in the Second Division, Mitchell was a regular member of the first team, but as a midfielder and later as a defender rather than the forward positions he occupied at the higher level.
He played only six times in 1979–80, returned to regular selection in the first half of the following season, and made his 72nd and final Newcastle appearance on 27 December 1980 in a 2–0 home defeat to Derby County.
He was a member of the Kuusysi team that won the 1984 Mestaruussarja (Finnish league) and reached the quarter-final of the 1985–86 European Cup, though he had left the club before that round was played.