Opposed to the restoration of the Stuart monarchy, he became an aide-de-camp to the Duke of Cumberland and during the Battle of Fontenoy in 1745, was shot in the face.

Joshua Reynolds' portrait (1753–55) shows the black silk patch he used to cover the scar on his cheek.

Upon inheriting his mother's estates in Greenock he sold Sundrum to James Murray of Broughton in 1758.

A small group of cottages on the estate were involved in the "manufacture of osnaburgs when visited by Bishop Richard Pococke in 1760.

In August 1768 he arrived as the ambassador at St Petersburg and was he was well received by Catherine the Great.