Colm spent some time at the Southampton academy before returning to Ireland where he played for St Patrick's Athletic's u19 side in the 2015 short season. In December 2015, Colm moved to Drogheda United where he made his first competitive appearance in a Leinster Senior Cup match against Bohemians on 22 February 2016. He made his league debut ten days later on the opening night of the 2016 season in a 2-1 win over Waterford United and went on to make 17 league appearances that year. Drogheda won promotion via the play-offs and Colm re-signed with the Drogs for their 2017 Premier Division campaign.

Having made 23 appearances in 2017 in all competitions (1 in cup and 22 in League), he then re-signed for the Drogs for the 2018 season.