Paisley born left half John Mitchell played close to a hundred games in a Celtic career which spanned near on seven years. Signed from Baillieston Thistle in November 1906 the hard-working left-half made his Scottish League debut in a 4-1 win at home to Partick Thistle on 1st December 1906.
However, generally he was used as cover for the first team, apart from the first two-thirds of season 1912-13.
He played in his first run of games in 1906-07, which earned him a place on the Copenhagen tour of 1907 and he played in goal in the first match.
In season 1907-08, he was a first pick for the first team but was competing for the role with Jimmy Hay, and ultimately lost out. Still he played a number of games in that season and picked up winners medals for the League Championship and Glasgow Cup. The Glasgow Cup was a great victory, as Celtic had to play Rangers three times after two draws in the initial matches, before finally prevailing 2-0 in the third and final match. Celtic only lost one game in that great 1907-08 season in which Mitchell played, which included matches defeating Rangers in both the Scottish Cup and League. Patsy Gallagher described his play as “a champion grafter at left-half“.
Thereafter he was used as cover, but stil helped Celtic win the League titles in 1908-09 & 1909-10. He played in other finals including the Glasgow Cup & Charity Cup Finals of 1910-11, Celtic losing 3-1 & 2-1 to Rangers.
He finally became a starter in season 1912-13, when Celtic lost the League to Rangers by just four points. His last game was a 2-1 win over St Mirren in April 1913. He eventually left Celtic in September 1913 when he joined Cowdenbeath before retiring in the summer of 1916. Despite 95 League & Cup appearances for Celtic, he never scored a goal for the Celtic first team in a competitive match.