Scots theologian, intellectual leader, and author.

Campbell entered the University of Glasgow at the age of 11, remaining until he was 20. After studying divinity at Edinburgh he became a clergyman in 1821. He was appointed to the parish at Row in 1825 and while there began to preach that salvation was guaranteed for all believers. This led in 1831 to his being declared a heretic by the General Assembly of the Scottish church, which closed its pulpits to him, depriving him of a living.

Campbell went into the highlands as an evangelist for two years but then acquired an independent congregation in Glasgow, where he remained for 26 years. His major treatise, The Nature of the Atonement (1856), went through five editions in his lifetime, and among his other works were Christ the Bread of Life (1851) and Thoughts on Revelation (1862).