Galvin was born on January 8, 1950, the son of a fireman. He attended Catholic schools, Fordham University and Fordham University School of Law. He previously worked as hearing officer for the New York City Department of Sanitation.
Galvin was the publicity director for the New York-based NORAID, an Irish American group fund-raising organization which raised money for the families of Irish republican prisoners, but was also accused by the American, British, and Irish governments to be a front for the supply of weapons to the Provisional IRA. Brian Jenkins, an expert on political violence at the RAND Corp, noted, "A group can move a dollar from its humanitarian budget to its weapons budget to some other budget and it's still a dollar. And if you reduce the burden an organization has to deal with in taking care of its people, you free money for weapons."
Galvin became a publisher of The Irish People in the 1980s. He was banned from Northern Ireland because of a speech he gave that seemed to endorse terrorism. In August 1984 he defied the ban, and slipped across the border. Shortly thereafter a man was killed during a rally in West Belfast when the Royal Ulster Constabulary tried to arrest Galvin.The following year Galvin attended a mass funeral for an IRA member killed when a makeshift grenade launcher he was trying to fire at a local police station exploded in his face. In 1989 Galvin was arrested and deported for violating the exclusion ban yet again.
- "How the peace train pulled out without Martin Galvin". Belfast Telegraph. May 24, 2010.
- "America's Leading Ira Supporter, Martin Galvin, Says He "Understands" Why Terrorists Targeted Mrs. Thatcher". People. September 5, 1984.
- "Martin Galvin's Message". The New York Times. August 15, 1984.
- Reference to Martin Galvin, Jr., cdn.pagesuite.com; accessed June 10, 2014.
- Wedding of Martin Galvin, Jr. and Emer Larkin, riverdalepress.com; accessed June 10, 2014.
- "Ties to Terrorism: Extremists Tap Into U.S. Money Tree". Los Angeles Times. March 3, 1988.
- "American Defies Ban and Attends IRA Services". Los Angeles Times. August 10, 1985.
- "Pro-IRA American Seized in Ulster; Had Been Barred". Associated Press. August 16, 1989.
- "'Traitors' — Martin Galvin's Rap for "Sell Out" by Sinn Féin". Sunday World. June 19, 2011.
- "Republican rebels gain strength". The Observer. June 24, 2000.