Armstrong, as a junior English army officer, was seeing action with Marlborough on the continent when he was detached, in 1711, to go with the ill-fated expedition of Admiral Hovenden Walker. The aim was to go up the St Lawrence, to attack Quebec, and, to put an end to the French presence in America. The Walker expedition, though mounted at great expense, was aborted before a shot was fired. History reveals that Walker, directly on account of his ineptitude, on his way up the St. Lawrence, ran a number of the British transports onto the shores of the St. Lawrence which resulted in a great loss of life. Enough, in our short biographical description of the man, to say that Armstrong was on one of these transports but managed to escape with his life. A large part of the sea born army was however saved and it was thought that Walker might have proceeded on to his objective; but he had had enough and wanted to go back to England; before doing so, 400 of the troops under Vetch were sent to reinforce the recently captured French port of Port Royal, now named Annapolis Royal.
Armstrong didn't stay long at Annapolis Royal, for, by 1715, he was back in England [Armstrong had a friend in high places, Thomas Pelham Holles (1693-1768), the Duke of Newcastle, "an incapable minister, but strong in courtcraft and intrigue ..." (Chambers Biographical Dictionary)]. Armstrong came back out again to Annapolis Royal, in 1720; but not as its commander; the top job was to go to Colonel Richard Philipps: Armstrong and Philipps took an instant dislike to one another. Armstrong wanted to take leave to go back to England; but, likely knowing that Armstrong would go and just complain, Philipps denied him leave -- indeed, Philipps sent Armstrong off to the little post on the northern end of the Nova Scotian peninsula, Canso (see map). (Armstrong was to become very supportive of Canso and saw it as a significant asset to the crown.) In 1721, an exchange took place, with Armstrong going to Annapolis Royal and Philipps to Canso. Armstrong knew an opportunity when he saw one, so, with Philipps not being at Annapolis Royal, to deny him, he sails off to England to make his representations. Out of this came an appointment for Armstrong as lieutenant-governor of Nova Scotia between 1725-1729 and in 1731 he became its governor, replacing Philipps.
Armstrong, a hard headed Irishman, was unpopular among his fellow officers. (An example of Armstrong's temper and intolerance can be given by making reference to the time when he banged a fellow officer over the head, while in the mess, with a "large Glass decanter full of wine." (DCB, vol. II, p. 643.) This fellow officer was George Vane (?-1722), an engineer who Armstrong had long known, both having come to Annapolis Royal in 1711 as a remnant of the Walker expedition. (Apparently, Vane was given to expressing Jacobite opinions.) "It was characteristic of him to meet a problem head-on, without much subtlety ... he displayed bad temper, arrogance, impatience, and lack of perception in dealing with people." (DCB.) "He was a brooding, moody man whose dark speculations found vent in violent action. ... His mind was full of plans and suspicious ...' (Brebner, New England's Outpost, p. 87.) He was a man "peevish in temper" and took "a serious view of trifling difficulties." (Hannay, p. 327.) If he had no success in dealing with the Acadians -- and he apparently did not -- it was likely because Armstrong didn't like them: "The French that I have to deal with are a perfidious, head strong, obstinate and as conceited a crew as any in the world." (As quoted by Brebner, op. cit., p. 88.)
On December 6th, 1739, Governor Lawrence Armstrong, "in a fit of despondency," takes his sword and commits suicide at Annapolis Royal. (See short footnote on Armstrong which Thomas Beamish Akins sets forth in his, Selections From The Public Documents, pp. 64-5.)