Mark started broadcasting as a founding member of Southside Radio in Bray, County Wicklow in Ireland in 1978. The following year he and a few others set up Bray Local Broadcasting or BLB which remained on air until 1988 when the Irish government finally set up a proper licensing structure. During its 9 years life, BLB campaigned for the introduction of Community Radio in Ireland and also became a beacon for the cause worldwide. During his time on Horizon Radio, Mark and producer Elaine Keogh won a Cultural Endeavour Award.
He started in TV and film post production in 1982 and set up his own company, High Wire in 1997 specialising in high end post production for the TV and film.

Since January 2025, Mark returned to his roots as producer/presenter of several podcast series. One notable 5 part series is on the history of BLB. He also works as a stand in presenter on Dutch station Radio Seagull and is a member of the Audience Council of Irish national broadcaster RTÉ.