The club was originally called Wigmore Athletic and were one of the founder members of Division Two of the Sussex County Football League for the 1952–53 season.The first season in the league brought instant success as they finished as Champions and gained promotion to Division one. The club then spent the next thirteen seasons in Division one during which time they won the league cup in the 1959–60 season. This period also saw the club make their debut in the FA Cup. At the end of the thirteen seasons in Division one the club was relegated to Division two but after two seasons were back in Division One. However the club was immediately relegated again, and had to wait until the end of the 1973–74 campaign to get back in the top Division, when they finished as Champions of Division two. The club competed in Division one for four seasons before being relegated to Division two where they stayed until the end of the 1987–88 Campaign.
At the end of the 1987–88 campaign Wigmore Athletic were relegated to Division Three of the Sussex County league. The club then changed its name to Worthing United when they amalgamated with local side Southdown FC. The newly named club took two seasons to escape from Division Three, when they gained promotion back to Division two as Champions. The club then spent the next fourteen seasons in Division two, with the final of these fourteen seeing the club gain promotion back into Division one as runners-up in the 2003–04 season. The club remained in Division one until the end of the 2008–09 campaign when they finished bottom of the division and found themselves back in Division two. They won promotion back to Division One in the 2010– 11 season under manager Dominic Di Paola.
In January 2013 Worthing United appointed Paul Curtis as their manager. In November 2013 John Foley was appointed as his replacement. The season ended with relegation back to Division 2. This season Malcolm Gamlen, the club secretary for over 20 years, sadly passed away. June 2014 saw another managerial change with Nigel Geary replacing John Foley. In his first year at the helm, Geary guided the club back to the new 'Premier Division' formerly known as Division One, after winning the league and cup double.
On 22nd August 2015 the club was hit by tragedy when Matthew Grimstone and Jacob Schilt were lost in the Shoreham Air Disaster. The team did not play again until 6th September, when they faced East Preston in an FA Vase tie. The match was played in front of more than 1000 spectators and the Mavericks won the game 2-1 in dramatic fashion. The 2015-16 season finished with Geary's men in 14th position, the clubs joint highest
Ahead of the 2016-17 season, Matt Evans was appointed U21 manager and Geary remained as First Team Manager. As the season began, The Mavericks experienced mixed fortunes and in November 2016, Nigel Geary departed the club and was replaced by Simon Funnell. At the end of the season, having secured survival, Funnell departed the club. Matt Evans was promoted to First Team Manager for the 2017-18 season. The vastly experienced Bill Clifford took the Managers role for the U21 team. The season finished with relegation for the Mavericks and Steve Taylor resigned from his role as Chairman, moving to local rivals Lancing. Changes were afoot in the summer of 2018 with Bill Clifford being elected as Chairman, and the decision was made not to enter an U23 team for the 2018/19 season, although many of that team were now in the First Team plans. Matt Evans retained his role as First Team manager. The 2018/19 season was an eventful one. In September, after a concerning dip in form, manager Matt Evans left the club. Curtis Foster took over the reigns but after just one match in charge, he left the Mavericks to take over at Shoreham. Adam Kipling replaced him and remained in place until the conclusion of the season, with a bottom-placed finish ending a forgettable season.
A relegation reprieve saw the Mavericks retain their Division One status, and 2019/20 was seen as a fresh start with the appointment of Danny Wood as manager. The U23 Development Squad was reintroduced. It was a season of two halves. The Mavericks took time to gel but after struggling for form early on, the team rose up the table and into the top half – competing for a top ten finish. The season was brought to a premature end, with the season declared null and void after the outbreak of the COVID-19 virus across the globe.
The 2020/21 season is now upon us and gets underway in strange circumstances. The season is starting a month later than would have been the case, and with the condensing of fixtures, certain cup competitions have been withdrawn for the season.