| Constituency | Dates |
|---|---|
| Sutherland | 1747 – 1761 |
Capt. Independent Co. of Foot 1745; capt. Loudoun’s Regt. 1746; ret. 1748.
Master of the Scottish mint 1756.
In 1754 Mackay was returned unopposed for Sutherland. James St. Clair, who had represented Sutherland 1736-47, wrote to James Oswald, 26 Jan. 1754:1Memorials of J. Oswald, 337. ‘In consequence of Mr. Pelham’s desire I have forebore to give the smallest opposition to Capt. Mackay ... though it was in my power to have done it effectually.’ Mackay was a Government supporter, who held a secret service pension of £300 per annum until he was given office in 1756.2Namier, Structure, 217, 428. On 2 May 1757 he voted with Newcastle and Fox on the Minorca inquiry; and during the 1757 negotiations was listed by Newcastle among the Scots personally attached to himself who would support an Administration from which Argyll might be excluded. Electoral considerations prompted Mackay’s vote against the Irish cattle bill; he was a teller in the division of 6 Mar. 1759. At the general election of 1761 he left Parliament in favour of his brother Alexander.
He died 25 June 1782.