Minister, philosopher and one time Moderator of the General Assembly of the Church of Scotland.
Gerard was born in 1728, the son of Gilbert Thomas Gerard (1660-1738), Minister of Chapel-Garioch, and Marjorie Mitchell (1704-1785). In 1757 he married Jane Wight (1730-1818), with whom he had several children.
He graduated MA from Aberdeen in 1744, before continuing his theological studies at Edinburgh. He became licensed as a Preacher in the Church of Scotland in 1748, before returning, in 1750, to Aberdeen as a Lecturer at his Alma Mater, Marischal College. He became a long-serving Professor in Aberdeen, holding the positions as Professor of Moral Philosophy at Marischal College from 1752 to 1760 and of Divinity first at Marischal from 1760-1771 and then at King's College from 1771 until his death in 1795. From 1760 until 1771 he was even Minister of Greyfriars Church in Aberdeen.
Gerard gained some reputation as a writer in his own time for his Essays on Taste (1759) and Genius (1774), and in 1780 a volume of his Sermons was published. On the occassion of the latter, Gerard's friend James Beattie wrote the following in a letter to Sir William Forbes dated May 23, 1780:
Dr. Gerard's "Sermons" in one volume 8vo, are just now sent me; but I have not had time to read a single page. I am sure they will be sensible and instructive. The author was my master, and I have the greatest regard for him. He was more than my master - he was my particular friend, at a time when I had very few friends.
Gerard came to see Boswell and Dr Johnson in Aberdeen in the morning of August 23, 1773, together with several other local scholars, including Principal George Campbell, Sir Alexander Gordon, Prof. Thomas Gordon, and Prof. John Ross.
He came to see them again after dinner that day, this time with Professors Leslie and MacLeod. They talked about Bishop Warburton (1698-1779), and Gerard accused the poet Thomas Warton (1728-1790), a friend of Johnson's, of "the most barefaced plagiarism" of the Abbé du Bos in his Observations on the Faerie Queence of Spenser (1754), with which Dr Johnson disagreed. Boswell, as was his habit, "talked of difference of genius to try if I could engage Gerard in a disquisition with Mr Johnson. But I did not succeed."