James Hadow was Principal of St Mary's College, St Andrews from 1707 till 1747. He was the born in Douglas, South Lanarkshire, Scotland on 13 August 1667. He died on 4 May 1747 at St Andrews, Fife, Scotland.
The Dictionary of National Biography suggests that Principal Hadow was educated abroad, probably due to the persecution of the Covenanters. It is probable that he was the same James Hadow who published two Latin theses at Utrecht in 1685 and 1686. He was ordained "2nd charge Cupar" in 1692 and on 30 October 1694 was transferred to "1st charge Cupar". In 1697 he married Isabel Tullidelph.
In 1699 he was made Professor of Divinity at St. Mary's College, University of St. Andrews. Between 1707 and 1747 he was Principal of St Mary's College, University of St Andrews. In 1705 he married Margaret Forrester.
The head of the University of St Andrews was the Rector who was elected annually and James was elected Rector on 14 occasions between 1706 and 1747.
Hadow was involved in many public controversies in the church. In 1720, he took a leading part in the Marrow controversy which bore on the views contained in The Marrow of Modern Divinity, published in England by Edward Fisher in 1645. In 1720, Hadow presided over a sub-committee for preserving purity of doctrine. Six so-called antinomian paradoxes were extracted from the work, on the subject of the sins of a believer. On 20 May 1720, an act of assembly was passed condemning the book, and instructing ministers to warn their people not to read it. Some of the "Marrowmen" seceded, but the rest, after a time, were silently permitted to promulgate their views.
Hadow acted against John Simson, Professor of Divinity at Glasgow University, who, being accused of Socinian views, was suspended from his Professorship in 1729.