Tottenham signed Mearns from Kettering Town in March 1903 to be understudy to Charlie Williams.[2] He made his debut on 5 October 1903 for Spurs in a Western League game to Queens Park Rangers where he kept a clean sheet in a 3–0 win.[2][3] By the end of the season Mearns helped Tottenham to win the Western League. He played a total of five Southern League games, four Western League games and four London League games and then moved onto Bradford City.
He played for Bradford City between June 1904 and May 1906.[4] He made 21 league and 2 FA Cup appearances for the club.[5]
Mearns joined Hartlepool United in 1908 for their inaugural season in the North Eastern League where they came fourth.[6] In the summer of 1909 he joined Barnsley.[7] He played in the Barnsley side who reached the FA Cup in 1910.[8]
^Dykes, Garth; Lamming, Doug (November 2000). All the lads: A complete who's who of Sunderland A.F.C. Polar Print Group Ltd. pp. 270–271. ISBN978-1-899538-14-0.