Born in 1888, Colbert was a native of Limerick. Prior to the Easter Rising he had been an active member of the republican movement, joining both Fianna Éireann and the Irish Volunteers. A dedicated pioneer, Colbert was known not to drink or smoke. As the captain of F Company of the Fourth Battalion, Colbert was in command at the Marrowbone Lane distillery when it was surrendered on Sunday, 30 April 1916. His execution took place on 8 May 1916.