Musgrave belonged to one of the chief Cumberland families. His grandfather, Sir Christopher Musgrave, a leading Tory politician, sat in Parliament for 43 years till his death in 1704. Under James II his father, Philip, M.P. Appleby 1685-7, obtained the post of clerk of the Privy Council, which descended to Musgrave via an uncle. In 1713 he was returned for Carlisle, where his family had a strong interest, though it was thought that if he had chosen to stand on the high Tory interest for the county he could easily have thrown out Gilfrid Lawson.
an occasion of treating about three score of the country people and, after they had drunk a good deal, the Duke and Sir Christopher Musgrave pulled off their coats and waistcoats, fell down upon their knees, and drank the Pretender’s health.
HMC Lonsdale, 123.
Knatchbull describes him as ‘a hot headed fellow’, who by his ‘heat’ was apt to play into the hands of the Government in the House of Commons and ‘spoil a fair game’. In 1725 he was one of five Tories who voted against the restoration of Bolingbroke’s estates.