In 1890 three local football clubs - Swifts, Slough Albion and the Young Men's Friendly Society - amalgamated to form Slough FC. They started off in the Southern Alliance, before joining the Great Western Railway Suburban League, which was formed from towns which had stations on the GWR. They joined the Spartan League in 1920, and remained there until the Second World War. In this period they won the Berks & Bucks Senior Cup five times, but league success eluded them.

Slough FC recorded their biggest ever victory - 17-0 against Railway Clearing House - in the 1921-22 season, and it was in the twenties and thirties that E.J. Norris became the club's all-time top goalscorer, with 343 goals in 224 games.

During the war, Slough FC were unable to use their ground, and this led to a merger with Slough Centre FC in 1943, the new club being called Slough United. The new club did not want to return to the Spartan League after the war, and instead became a founder member of the new Corinthian League, a move which led to their being nicknamed 'the Rebels'.

The two clubs split again in 1947, with Slough FC becoming Slough Town later the same year.