Born in Athea, Co Limerick he was an organiser for Fianna Éireann in Limerick. After his intermediate certificate he got a job in the Great Southern and Western Railway Co. Along with Con Colbert, Heuston was involved in the education of the schoolboys at Scoil Éanna, organising drill and musketry exercises. During the Howth gun-running operation in 1914, he was in charge of a trek cart which successfully moved a large quantity of rifles to Dublin.
A section of the First Battalion of the Volunteers, under the leadership of Heuston, occupied the Mendicity Institute on south of the Liffey at Usher’s Island, holding out there for two days. He was executed on 8 May 1916. Heuston Railway station in Dublin is named after him. Ten days after the surrender he, along with Con Colbert, was tried and sentenced to death. He was executed at Kilmainham on May 8, 1916.