The son of the 3rd Viscount Charlemont, he was born in Dublin, and succeeded his father as 4th Viscount in 1734. The title of Charlemont descended from Sir Toby Caulfeild (1565-1627) of Oxfordshire, England, who was given lands in Ireland, and created Baron Charlemont (the name of a fort on the Blackwater), for his services to King James I in 1620. The 1st viscount was the 5th baron (d. 1671), who was advanced by Charles II.
Lord Charlemout is historically interesting for his political connection with Henry Flood and Henry Grattan; he was a cultivated man with literary and artistic tastes, and both in Dublin and in London he had considerable social influence. For various early services in Ireland he was made an earl in 1763, but he disregarded court favors and cordially joined Grattan in 1780 in the assertion of Irish independence.
He was president of the volunteer convention in Dublin in November 1783, having taken a leading part in the formation of the volunteers; and he was a strong opponent of the proposals for the Union. His eldest son, who succeeded him, was subsequently (1837) created an English baron.
His Life, by F Hardy, appeared in 1810.
{| border="2" align="center"
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|width="30%" align="center"|Preceded by:
New Creation
|width="40%" align="center"|Earl of Cork
|width="30%" align="center" rowspan="2"|Followed by:
Francis William Caulfeild
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