[1] In 1798, on the death of his great uncle Henry Noel, 6th Earl of Gainsborough (on whose death the earldom became extinct), Gainsborough and the rest of the family assumed, by Royal licence, the surname of Noel in lieu of his patronymic.

[3] Gainsborough succeeded his father as Member of Parliament for Rutland in 1808, a seat he held until 1814.

[2][4] In 1823, he succeeded his mother as the 3rd Baron Barham in the Peerage of the United Kingdom and entered the House of Lords.

Before her death on 20 September 1818, they were the parents of one child:[3] His third marriage was on 29 July 1820 to Arabella Hamlyn-Williams (d. 1829), second daughter of Sir James Hamlyn-Williams, 2nd Baronet of Clovelly Court and the former Diana Anne Whitaker (a daughter of Abraham Whitaker).

Together, they were the parents of:[3] Gainsborough died in June 1866, at the age of 84, and was succeeded by his son from his second marriage, Charles.