Liam played underage football with Arklow Town before joining UCD's U19 squad for the 2015 and 2016 seasons. In 2016 he was involved with the senior team during their pre-season friendlies and he made his senior debut in a 4-1 win over Cabinteely at Belfield on 8 July 2016. He scored his first senior goal in a 1-1 draw away to Athlone that September and finished the season with two goals from 13 league appearances.