He was born in Ireland and emigrated to America while in his early twenties, becoming an ironmaster at Warwick Furnace and Coventry Forge. He was elected to the provincial Assembly in 1764, and was a member of the Committee of Correspondence and the Committee of Safety. He was appointed a delegate to the Continental Congress in 1775 to replace a member of the Pennsylvania delegation who refused to support independence. He arrived too late to vote for independence, but in time to sign the Declaration of Independence. He returned to Pennsylvania to serve as Supreme Council, but retired due to ill health after only six weeks in the office.