Born in Errol, Perthshire, in 1680. He graduated from St. Andrews with an M.A., in 1702. He was licensed by the Presbytery of Cupar, in 1708. Nairn was ordained by the Church of Scotland, in 1710, at Abbotshall, Fifeshire, but he was restless in the Revolution church. In 1737, he joined the Associate Presbytery, or Seceders, a connection that would be temporary and preparative to his later alignment with the Old Dissenters. As a result of this connection, he was deposed by the Church of Scotland, in 1740. In 1742, and into 1743, he became involved in controversy with the Associate Presbytery over their proposal to renew the National Covenant and Solemn League. In their act for renewing the Covenants, the Seceders condemned the views of the Old Dissenters over their views regarding the use of arms in resisting uncovenanted governments. Nairn objected to this statement and dissented from the action of the Seceder Presbytery in adopting that resolution condemning those who were opposed to the civil authority of the then civil authority. Thus, on February 3, 1743, he joined with John M'Millan and, on April 4, the Societies called him to be one of their ministers. Becoming the second minister, Nairn was part of erecting the Reformed Presbytery which was duly constituted on August 1, 1743. Soon after, the Reformed Presbytery licensed Alexander Marshall, who had been a student of divinity for some time. On November 15, 1744, having been called by the societies, he was set apart to the office of the ministry with Mr. Nairn preaching the ordination sermon. During this time, he was sent on one mission to Ireland, accompanied by Mr. Marshall, to minister to their adherents there. Not long after, he was brought to censure for some ecclesiastical misdemeanor. As a result, in 1745, Nairn seceded from the Reformed Presbytery and, in 1747, the Seceders once more served him with a libel. This case dragged on until he was finally excommunicated by the Associate Presbytery, in 1750. The following year, in 1751, he was re-admitted to the Church of Scotland upon confession of his "sin" in leaving her communion in the first instance. He died in 1764.