O'Doherty joined the IRA in 1958 in his native Carrick-on-Suir, County Tipperary, and participated in the Border Campaign.
O’Doherty bergabung dengan IRA pada 1958 di daerah asalnya Carrick-on-Suir, County Tipperary, dan berpartisipasi dalam Kampanye Perbatasan.