In 1945, they won the FAI Intermediate Cup by beating fellow future League of Ireland members Cobh Ramblers 4–2 in the final.

A second invitation to join the League of Ireland was accepted on 22 July 1979, when Cork Celtic were expelled for not having their financial affairs in order.

Dr. Tony O'Neill, who was General Manager when the club joined the League, remained in that role until his untimely death from cancer in October 1999.

The draw pitted them against Everton, then one of the leading sides in England and boasting players of the calibre of Neville Southall, Kevin Sheedy, Graham Sharp, Peter Reid and Andy Gray.

Another remarkable performance was to follow two weeks later, as a solitary Graham Sharp goal gave Everton a 1–0 win.

Joe Hanrahan signed for Manchester United for IR£30,000, Ken O'Doherty moved to Crystal Palace, and Alan O'Neill left for Dundalk.

Their opponents were the Bulgarian side PFC Velbazhd Kyustendil, who boasted a couple of full Bulgaria internationals, including Ilian Stoyanov, who would go on to represent his country in the 2004 European Championships.

After enjoying a successful first season, the team only just avoided relegation in 2002–03 and were eleven points adrift when Doolin left to take over at Drogheda United in September 2003.

UCD marked their return to the Premier Division with a highly creditable 1–1 draw away to two-time reigning champions Shelbourne.

There was a bright point in College's ultimately indifferent season when they got into the League Cup final after a last-gasp 2–1 victory over Shelbourne in the semi-final at Tolka Park.

With a largely new team, UCD bounced back to the top flight of Irish football at the first time of asking by securing their second First Division title, promoted after a 5–0 away win over Athlone Town in the penultimate match of the season on 30 October 2009, ahead of former Premier Division teams Shelbourne, Longford Town, Waterford United FC as well as a strong challenge from recently formed Sporting Fingal FC.

In 2011 the club qualified for the Setanta Sports Cup, an All-Ireland competition, where they lost to Lisburn Distillery FC 2–0 over two legs.

At the beginning of the 2014 season Russell was replaced by former coach Aaron Callaghan, who had to serve out a five-game dug-out suspension awarded while at rivals Bohemian FC.

In 2017, the club competed in the UEFA Youth League, losing on penalties to a Molde FK which included Erling Haaland.

[5] In the 2022 League of Ireland Premier Division, UCD spent most of the season battling with Finn Harps to avoid automatic relegation.

A 15th-minute goal by Tommy Lonergan, his 12th of the season in all competitions, led UCD to a 1–0 win and ensured their survival in the Premier Division.

[6] UCD AFC is noted for its highly regarded scholarship scheme, which gives players the chance to combine senior football with the opportunity to earn a college degree.

Todd Andrews, future Chairman of CIÉ and RTÉ, and his son David Andrews, a future Minister for Foreign Affairs, both played in the Leinster Senior League for the club, as did Brian Lenihan, who scored in a 1953 FAI Cup tie against Sligo Rovers and later ran for President of Ireland.

Moran also won an All-Ireland Gaelic football winner's medal with Dublin in 1976 while at UCD, as would Jason Sherlock nineteen years later.

Conor Sammon, Enda Stevens and Andy Boyle also won senior international caps having started their careers with UCD.

Former Sky Sports and current Setanta Sports pundit Paul Dempsey played for one season in 1982/83 before taking up a job with the BBC Gavin Whelan (nephew of Ronnie Whelan) and Pat Jennings (son of Northern Irish international Pat Jennings) played for UCD in the mid-2000s.

UCD has a small fanbase, which included until his untimely death the Father Ted actor Dermot Morgan, an occasional visitor to Belfield.