His mother was the author of the verse drama, "The Siege of Jerusalem" (1769). He succeeded his father as Earl of Strathmore and Kinghorne when the latter died at sea on 7 March 1776. He had a long affair with the commoner Mary Milner, the beautiful daughter of a gardener.
According to some versions (notably offered by Augustus Hare) he went through a false ceremony of marriage with her.
From 30 June 1796 to 24 October 1806 and again from 9 June 1807 to 29 September 1812, he sat as a Scottish Representative peer in the House of Lords. They had one son:
John Bowes (1811–1885), known as Lord Glamis from birth until 1820, and sent to Eton under that name. The Earl was created Baron Bowes on 1815 and held this as a subsidiary title to his death.
The trustees were also required to pay Mary £l,000 p.a for life.
The Scottish courts agreed that by marrying Mary, John had been legitimized under Scottish law, but since both parties (notably the father) were domiciled in England, English law would prevail. And Scottish law required Scottish domicile of the parents for the son to have been legitimated.
lieutenant was on the point of domicile that John"s legitimation failed. His secondary title as Baron Bowes became extinct.
Mary, now Dowager Countess of Strathmore, married in 1831 her son"s tutor William Hutt, and died in 1860.
Her son John Bowes married twice, but had no issue.
