In 1678 he married the former Earl's widow, Mary Campbell, the Countess of Caithness, an economical step which saved him his obligation to pay her 12,000 marks a year.
The natural heir, a younger son of the fifth earl however, was subsequently confirmed in his lands and titles by the Parliament of Scotland, so on 13 August 1681, Campbell obtained a new patent which made him Earl of Breadalbane and Holland, Viscount of Tay and Paintland, and Lord Glenorchy, Benederloch, Ormelie and Wick, in the Peerage of Scotland, with special power to nominate his successor from among the sons of his first wife.
On 30 June 1691 he met the Jacobite chiefs; he persuaded them to refrain from acts of hostility until October, gaining their consent by threats and promises rather than by the distribution of the money, which, it was believed, he retained himself.
[1] When asked to give an account of the expenditure to parliament, he replied Breadalbane had a reputation for double-dealing which led to a lasting belief that he had a direct hand in the Massacre of the Macdonalds of Glen Coe in February 1692.
[citation needed] However, the discovery of his negotiations with the Jacobite chiefs caused his imprisonment in Edinburgh Castle in September, but he was released when it was known that he had been acting with William's knowledge.
His cooperation with the English government in securing the temporary submission of the Highlands was inspired by no real loyalty or allegiance, and he encouraged the attempted French dissent of 1708, refusing, however, to commit himself to paper.