Mark played with Finn Harps U19 side in 2014/15 and made his league debut for the club away to Wexford Youths on 30 September 2014, his only league appearance of that season. He continued to be with the u19 squad for the 2015 season before joining Cockhill Celtic at the end of the season. However, he returned to Finn Harps in February 2016 and was included in the senior squad for the Premier Division campaign.

Mark re-signed with Finn Harps for the 2019 season. Mark appeared 27 times in 2019 for Harps, including both playoff games versus Drogheda United. Mark then re-signed for Finn Harps for the 2020 campaign.