Born in Saintfield, County Down, Ireland, February 13, 1778. He came with his parents to America in 1791, and settled in Franklin County, Pennsylvania. In 1798, he was engaged as a teacher in Shippensburgh, Pennsylvania, and soon afterwards entered Jefferson Academy at Canonsburgh, Pennsylvania, where he finished the course in 1802, before the establishment of Jefferson College. He then began to study medicine, finished the course in 1805, and settled as a physician in Mercer, Pennsylvania. In 1807, Drs. Alexander McLeod and Samuel B. Wylie sought an interview with him at Pittsburgh, and informed him that Presbytery would have his scruples removed and him enter upon the work of the ministry. He was after close examination, licensed by the Reformed Presbytery, October 7, 1807. He was later ordained and installed pastor of the united congregations of Galway and Duanesburgh, New York, August 8, 1808. He was a learned and voluminous writer upon various subjects, including a work on the Shorter catechism entitled "The Shorter Catechism Analyzed, with Proofs." He died at the home of his son, E. D. McMaster, in New Albany, Indiana, March 17, 1854.