The club was formed in 1868 and in their early years played under several names including Harefield Victoria and Breakspear Institute, and played in the local Uxbridge Leagues. In 1934 the club merged with Harefield FC to become Harefield United, and played in the Uxbridge & District League. After the war the club moved to the Great Western Combination in 1947, winning the league once in the 1950–51 season. After the Great Western Comibuination league the club played in the Parthenon League in 1964, and winning the league in their debut season. Two seasons later they joined the Middlesex league in 1966. During their 5 seasons in the Middlesex league the club went on to win the league title four times and the league cup twice. In the 1971–72 season the club then joined the Spartan League – Senior Section, staying there for four seasons,while also making their Debut in the FA Vase in the 1974–75 season, before joining division two of the Athenian league for the start of the 1975–76 season. The club made their debut in the FA Cup in the 1979–80 season. After nine seasons in the Athenian league the club joined the Isthmian League Division Two North for two seasons before switching to Division two south. The club then spent seven seasons in Division Two South, which was renamed to just Division two in 1991, suffering relegation at the end of this period to Division three. The club then remained in Division three until the 1996–97 season when they left the Isthmian league to join the Spartan league, due to a lack of funds to carry out necessary ground improvements required for the Isthmian league. A season after joining the Spartan league, they became founder members of the Spartan South Midlands League Premier Division South, when the London Spartan League and the South Midlands League merged. A season later after another league re-organisation they were placed in the Senior Division, which after three seasons was renamed division one. The club in the newly named Division one finished as runners-up that year, and won the League Cup. With the club for the 2002–03 season now in the premier division, they competed in the Premier League Cup, finishing as runners-up at their first attempt. The club also had more success that year by winning the Challenge trophy beating Dunstable Town 4–1 over two legs. Furthur cup success continued the following season with the club winning the Premier League Cup, overcoming Brook House in the final and getting beaten 2–1 by Wealdstone in the Middlesex Senior Charity Cup. The club has since remained in the Spartan South Midlands League Premier Division finishing runners-up twice, in the 2006–07 season and the 2008–09 season where they lost out on goal difference against Biggleswade Town. Manager Ian Crane left to join A.F.C. Hayes in the summer of 2012, and he was replaced by Uxbridge reserve boss Phil Granville. However, Granville left in the summer of 2015 to become Hanwell Town's manager and he was replaced by Jason Shaw in May 2015.. In the 2018-19 season, Jason Shaw led Harefield United to promotion from the Spartan South Midlands League Division One with five games to spare in his fourth season with the club. The club went the whole league season unbeaten.
Ground
Harefield United play their games at Preston Park, Breakspear Road North, Harefield UB9 6NE. In 2010 the ground won the Steps 5 and 6 National Award for Groundsman of the year.
