The club was established in 1949 and initially played in the Grantham & District League. They remained in the Grantham League until joining Division One of the
Central Alliance in 1967. However, after a single season in the Central Alliance the club transferred to Division One of the
East Midlands Regional League. A fifth-place finish in 1973–74 saw Harrowby promoted to the Premier Division. They subsequently moved up to Division One of the
United Counties League. Although the club won the division in
1991–92, they were unable to take promotion to the Premier Division. However, after finishing as Division One runners-up in
2002–03, the club were promoted to the Premier Division. The
2005–06 season saw Harrowby finish bottom of the Premier Division, after which they dropped back into the Grantham & District League. The club spent the 2007–08 season in the
Lincolnshire League, finishing bottom of the table, before joining the Supreme Division of the
Central Midlands League. In 2009 they were renamed Grantham Rangers, but folded at the end of the 2009–10 season, which had seen them finish bottom of the Supreme Division. A new Harrowby United was established in 2012 when Grantham & District League champions Beehive United changed their name to Harrowby United upon taking promotion to Division One of the United Counties League. In
2013–14 a third-place finish saw the club promoted to the Premier Division. They were relegated back to Division One after finishing second-from-bottom of the Premier Division in
2016–17. In
2023–24 the club finished fifth in Division One, qualifying for the promotion play-offs. After beating
Clipstone 4–1 in the semi-finals, they defeated
Newark Town 2–1 in the final to earn promotion to the Premier Division North. ==Club officials==