He was born in 1721 the son of Archibald Coates and his wife Jean Campbell heiress to the Clathick estate in the parish of Monzievaird in Perthshire.
[1][2] John became 6th laird of Clathick but spent much of his time as a tobacco merchant in Glasgow where he was one of the "Virginia Dons".
He owned a large swathe of land in the city known as the Ryding district.
[5] In 1783 he was co-founder of the Glasgow Chamber of Commerce along with Gilbert Hamilton of Glenarbuck.
Their eldest surviving son Archibald Campbell (1756–1820) inherited the Clathick estate on the death of his father.