In that year's Annual report stakes the Hon Sec. Jim Younger noted that "One can visualize in this growing suburb, Leixlip Utd. may in time become of the foremost clubs in the country.." After two years in the A.U.L third division, the team left the A.U.L and enter the Leinster Senior League in 88/89 entering into Division 1A and Division 2B during the following half a decade the club were relegated into Division 1b  The Club remained between the 1A and 1B divisions of the Leinster Senior League. The appointment of John Martin marked a period of incomparable success for the Senior team. One the Final day of the 2011/2012 season the club won promotion to Senior 1 having been relegation candidates early on in the season to beating St. James Gate in the Iveagh Grounds and on the final day of the season beating fierce local rivals Confey 3-1 away in St.Catherines Park to claim the title it was the start of what would three back to back promotions.  2012/2013 saw Leixlip win the Senior 1 title comfortably ahead of UCD and Verona FC and in doing so they reached the highest tier of the Leinster Senior League; Senior Sunday. This would be the first time the club would ever compete at this level. In 2014/2015 Leixlip where immediately relegated from the Senior division and Joh Martin stepped down as Manager. After his departure, former Saturday side Manager Brendan Lennon took over the club as they embarked upon their Senior 1 Sunday campaign in 2015/2016 campaign leading them to a respectable 7th place in his first season. The 2016/2017 season was a thrilling campaign for Leixlip in which they won promotion to the Senior division again for the second time ever in the club's history. This season saw Leixlip play some thrilling attacking football finishing third in the league behind Newbridge and Portmarnock respectively. Only losing one game between November and May and a 2-1 win over Senior Division challengers Crumlin United in the Metropolitan Cup being two highlights for the club during this season. The 2017/2018 season saw Leixlip relegated from the Senior Division after a valiant effort to stay up, Brendan Lennon resigned at the end of the season following a 1 nil victory to recently crowned League Champions Blubell United.