Background
He was the son of Joseph Leeson, a brewer in Dublin, and Mary Brice, daughter of Alderman Andrew Brice, Sheriff of Dublin.
He was the son of Joseph Leeson, a brewer in Dublin, and Mary Brice, daughter of Alderman Andrew Brice, Sheriff of Dublin.
The name Leeson is found in Ireland before 1680. Four Leesons occurred in the lists of army personnel in the Ormond Manuscripts, the earliest in 1644. Between 1743 and 1756, Leeson sat in the Irish House of Commons for Rathcormack.
He was created Baron Russborough, in the County of Wicklow, on 5 May 1756, Viscount Russborough, of Russellstown in the County of Wicklow, on 8 September 1760, and Earl of Milltown, in the County of Dublin, on 10 May 1763.