[1] He first went to sea in merchant ships, and later served in the Royal Navy, as surgeon's servant, able seaman, and midshipman, in the Windsor, Firebrand, Amazon, Aleide, Hussar, and Eolus.

[1][2] Promoted post-captain on 18 April 1778, Blair captained Vice-admiral Byron's flagship, the Princess Royal, of 90 guns, in the action off Grenada on 6 July 1779, and was later appointed to the Nonsuch.

[2] From 2 March 1781 he commanded the Dolphin,[2] of 44 guns, and in her saw action in the bloody battle on the Dogger Bank on 5 August 1781.

Blair's conduct was distinguished, and won for him the special approval of the admiralty, and his appointment to the Anson, a new 64-gun ship, then fitting for service in the West Indies.

[1] In January 1782 Blair sailed in company with Sir George Rodney's fleet, and on 12 April, when the French were completely defeated in the battle of the Saintes, to leeward of Dominica, the Anson was in the leading squadron under the immediate command of Rear-admiral Drake, and was heavily engaged from the very beginning of the battle.