Portesham United were founded back in the 19th century and have been Dorset League champions on at least 3 occasions. There are few accurate records of The Possums' early history, however, the club enjoyed great success throughout the seventies and eighties. The club was then disbanded in the early ninenties due to the clubs growing stature attracting players from further afield resulting in a move into Weymouth to become Weymouth United which brought down the curtain on nearly 100 years of football in the village.

In 2005, brothers and Portesham residents Paddy + Matt Croxson formed a Weymouth Sunday Football League side featuring two former Portesham league and cup winners in Billy Blackmore and Greg Ayles and three local Portesham lads. The club gained two promotions in three seasons with Paul Marks masterminding the clubs early progress. After five seasons in the Weymouth Football League, the club commitee decided it was time to expand its horizons and a move into the Dorset League was mooted.

After several meetings, the decision was taken to reform Portesham United and long time Portesham resident John Hensby was elected as club president and the club was given the green light from the Dorset FA to enter the Saturday League for the 2010/11 season. Due to Portesham's illustrious history and the teams performances in the Weymouth Leagues, the FA decided to place us straight into Division 2. The club endured a disastrous campaign in 2010/11 finishing bottom of Division Two and were relegated to Division Three for the 2011/12 season.

The club also organises an annual Charity Match at Dorchester FC's Jewson Stadium raising money for the Air Ambulance.