Murray inherited considerable estates in Wigtownshire, Kirkcudbright, and Ireland. In 1761 he stood for Wigtownshire on the Galloway interest but was narrowly defeated by John Hamilton of Bargany. His petition was strongly supported by Rockingham, an old friend, who wrote to Devonshire, 28 Nov. 1761:
Lord Bute wished him not to proceed but upon Murray’s seeming determined Lord Bute sent him word that he had no objection ... and should not interfere. Your Grace knows how far that goes and I believe Mr. Murray is prepared to find Mr. George Grenville and all those ... particularly connected with Lord Bute will ACCIDENTALLY be all against him.
A compromise was negotiated; Hamilton vacated the seat and Murray was returned.
James Boswell wrote of Murray in September 1762:
He is a most amiable man, has very good sense, great knowledge of the world and easy politeness of manners. His lady is very beautiful ... They present a pleasing picture of matrimonial felicity ... evergreens in love.
His wife’s relations, however, were bitterly chagrined when Murray followed Rockingham into opposition and voted against the peace preliminaries. In the debate on Wilkes, 15 Nov. 1763, James Stuart Mackenzie noted that in the first division Murray voted with Opposition, but in the second joined all the other Scots present in voting with Administration.
On Grenville’s fall, Rockingham secured for Murray the salary of the receiver-general of the land tax in Scotland, a place incompatible with a seat in Parliament then held by Allan Whitefoord, who made his profit by the use of the balances in his hands.
Obliged in 1768 to surrender Wigtownshire to his brother-in-law Keith Stewart, Murray transferred to Kirkcudbright Stewartry and compelled the withdrawal of Bute’s friend, John Ross Mackye. In the new Parliament he remained constant to Rockingham in opposition, but lost his place in 1773.
You must be the best judge how far your re-election at the general election is practicable ... and also how far the expense may be agreeable or convenient ... Your principles and your kind friendship to me you have ever most fully shown and I cannot wonder that you and others should be tired out with the drudgery of Parliament and in continuing a system of politics which affords little prospect of success.
Murray decided to abandon the contest and retired to his estates. On North’s fall he applied to Rockingham for any good Scottish employment except that held by Keith Stewart.
