Martin was part of the first group of Irish soldiers to be sent to the Congo on UN duty in 1960. He was on duty the night of the Jadotville massacre, which resulted in the deaths of nine Irish soldiers, but was stationed some distance away from where the attack occurred.

Martin subsequently served with the UN in Cyprus in the mid-1960s and remained a member of the Defence Forces until 1980s. When he retired, he held the post of sergeant surveyor.

A native of Cathedral View, Martin married Mary (nee Devine) in October 1965. The couple lived in Irishtown, where they reared their five children.  Martin was a talented hurler in his younger days, lining out for the now defunct Pearses club. He encouraged his family to become involved in sport. His son Garry excelled in tennis and is now head coach with Tennis Ireland.