He was born at Grosvenor Square, London, in 1767 and educated at Eton and St John's College, Cambridge.

[1][2] In 1790, he was elected Member of Parliament for Cardiff, a seat he held until his death.

[1] He took over from his father as Colonel of the Glamorgan Militia in 1791 and was also Lord-Lieutenant of Glamorganshire between 1793 and his death.

[1] They had two sons, who both added the surname "Crichton" before that of "Stuart" in 1805:[1] Lord Mount Stuart died at Bassingbourn Hall near Stansted, Essex, in January 1794, only 26 years of age, a month after being injured in a fall from his horse.

[1][2] Lady Mount Stuart survived him by three years and died in July 1797, aged 24.