Collier was a retired army officer who came out with the first British settlers in 1749 (see "The Founding of Halifax"); he was accompanied by his wife.1 He was born in England and had a few friends in high places including the Earl of Halifax. Other then that, there is little we know of Collier's life prior to coming to Nova Scotia.
Cornwallis, thinking Collier belonged "to the better sort of inhabitants," on setting up a civil government in the new establishment of Halifax appointed him (July 18th, 1749) as a Justice of the Peace together with three others.2 On January 27th, 1752, Collier was appointed to Council and was on Council when it passed the fateful resolution of July 28th, 1755, which led to the deportation of the Acadians that year.
Collier was, in time, and no doubt because of his connections back in London, appointed as a judge of the Court of Vice-Admiralty.
I see (DCB) where Collier was described as having "a strong personality and was a man of consistent views," qualities, no doubt which stood him in good stead as a judge. His strong personality, however, was to bring him into conflict, in later years, with both Governor Lawrence and with his fellow councilor and judge, Jonathan Belcher. Collier was accustomed to winning any argument on how to proceed with matters, usually because of his propensity to send petitions to his friends back in England.
I further see (DCB) where Collier was to eventually pick up large tracts of Acadian lands in the area of Pisiquid, the area we know today as Falmouth, though, at his death, all of his estate was liquidated in order to pay off his accumulated debts. He was to die at Falmouth in 1769.
 Akins, Selections From The Public Documents, in a fn at pp. 255-6
 Akins, History of Halifax City NSHS#8 (1895), p. 15.)