Born in Rush, Dublin, Clarke worked for the Sinn Féin Bank, and was active in the Easter Rising. Located in the vicinity of Northumberland Road and Mount Street Bridge, he took part in some of the fiercest fighting of the week, in an area where the Sherwood Foresters famously marched into a waiting party of Volunteers, who had taken up strategic positions in the hope of ambushing men marching into the city from Dún Laoghaire. Joe was with a small band of men in the Parochial Hall building on Northumberland Road, who caused havoc for British troops advancing towards Mount Street Bridge. When the Volunteers eventually ran out of ammunition, they attempted to escape by sneaking out into Percy Place behind the building. They were intercepted by British soldiers. Upon being searched, Joe Clarke, was found in possession of a revolver, and placed with his back to a door. With his own revolver he was fired upon, the bullet pierced the door just above his head and the door was immediately thrown open, an indignant doctor rushed out, having narrowly escaped being shot as he attended one of the many wounded British soldiers; and, after an almost miraculous escape, Joe was led away, with his hands bound behind his back.

Joe remained bitter in later years towards Éamon de Valera, who commanded a sizable force of men at the nearby Boland’s Mills, remembering that “there was any amount of men in Boland’s Mills, and although we sent for reinforcements, we didn’t get any.” In one interview, he went as far as to say he always looked on Dev as “a dictator” within the movement.