[3] He joined the Army, serving during the War of the Spanish Succession where he saw action at the Battles of Oudenarde and Malplaquet.

[4] His career benefited from his brother's close connection to the Army's Captain General the Duke of Marlborough.

[3] Atterbury describes Cadogan as "a bold, bad, boistrous, blustering, bloody, booby.".

[3] Upon his brother's death in 1726, he succeeded to his barony of Cadogan of Oakley, under special remainder, but not to the earldom, and gave up his seat in the House of Commons.

[3] On 25 July 1717, Cadogan was married to the heiress Elizabeth Sloane at the Church of St George the Martyr, Queen Square, London.