Sam Johnson began his career with home town club Colne in 1904 and was given an opportunity of Second Division football with Blackpool a year later.

He had a dream debut for the Seasiders, scoring in a 2-2 draw against Gainsborough Trinity on 16 September 1905. He never lived up to the promise of that opening and failed to score in his 33 other League games for Blackpool. He returned to Colne and Lancashire Combination football in 1907, but then had spells in the Southern League with Exeter City (1908/09) and Coventry (1909-11).

Leeds City gave Johnson the chance to resurrect his league career when they signed him in 1911. He was given his debut in the second game of the season and scored once in his seven appearances in 1911/12, lobbing beautifully over the Grimsby keeper's head at Elland Road in January. He was released after the arrival of Herbert Chapman at the end of a season that saw City having to apply for re-election and Johnson never played professionally again.