[1] He had inherited the Dangan and Mornington estates in County Meath on the death of his first cousin Garret Wesley in 1728.

His son, the second Baron, was made the first Earl of Mornington in 1760, and at the same time also became Viscount Wellesley, of Dangan Castle in the County of Meath, also in the Peerage of Ireland.

He was succeeded in the other titles by his younger brother William Wellesley-Pole, 1st Baron Maryborough, who became the third Earl of Mornington.

Lord Mornington is chiefly remembered for his dissipated lifestyle which brought about the destruction of the Tylney family estate of Wanstead House.

He had been the subject of a bitter custody battle between his father and his two maternal aunts (who had wanted him to be placed under the guardianship of his great-uncle the Duke of Wellington) and later fought a legal battle with his father over the sale of contents of the family seat Draycot House.

He left all his landed property to his father's cousin Henry Wellesley, 1st Earl Cowley.

He was succeeded in his Irish titles by his first cousin once removed, Arthur Wellesley, 2nd Duke of Wellington.

His grandson Sir William Wellesley (died 1602) lived at Dangan Castle, County Meath.

His daughter, Katherine, married Sir Henry Colley (or Cowley) (16th century), of Castle Carbery, County Kildare.

One of Sir Henry's sons, Dudley Colley (or Cowley), was a member of the Irish Parliament for Philipstown.