On his return to Great Britain following the accession of James VII and II, he brought letters of personal recommendation from Louis to the new King.

He was confirmed in the titles of Duke of Hamilton, Marquess of Clydesdale, Earl of Arran, Lanark and Cambridge and Lord Aven, Polmont, Machansyre, and Innerdale.

[1] This regrant of title was presumably because of the loyalty of Arran's parents to the king, as his own affection to the House of Orange was questionable due to his suspected Jacobitism.

Historian Stephen Mullen referred to the scheme as a "mercantilist venture designed to improve personal fortunes and Scotland’s balance of trade through colonisation and exploitation".

[3] As part of the scheme, Hamilton planned to import African slaves "to be worked to death" at local gold mines in the region after they had come under the colonists' control.

To the detriment of his royal future, Hamilton's political conduct proved ineffective and he wavered between both the Court and the National parties.

On the day of the final vote regarding the Anglo-Scottish union, Hamilton abstained and remained in his chambers at Holyrood Palace claiming to be indisposed by toothache.

On 15 November 1712, Hamilton fought a celebrated duel with Charles, Lord Mohun, in Hyde Park, Westminster, in an episode narrated in Thackeray's The History of Henry Esmond.

Following the death without an heir of Fitton Gerard, third Earl of Macclesfield, in 1702, a disagreement had arisen over who should succeed to his extensive estates, based at Gawsworth Hall, Cheshire.

Questions about why John Hamilton did not stay to attempt to arrest Macartney if he had thought that such a crime had been committed brought suspicion on his testimony.