In the first European settlement of Australia in 1788, Collins was the founding Lieutenant Governor of the Colony of New South Wales. In 1803 he led the expedition to found the first, short-lived, British settlement in what was later to become the Colony of Victoria. In 1804, Collins became the founding Lieutenant Governor of the Colony of Van Diemens Land, which in 1901 became the state of Tasmania.
Collins was born in London, the third child of Major-General Arthur Tooker Collins (1718-1793), of the Royal Marines - the son of Arthur Collins (antiquarian) - by his wife Henrietta Caroline Fraser, daughter of George Fraser of Park and Cuba Court (see entry under 'Architecture, buildings and structures' of Banagher), High Sheriff of King's County.
A Compendium of Irish Biography (1878), states that he was born at the home of his maternal grandparents in County Offaly, then known as King's County. Collins went to Exeter Grammar School before joining the Royal Marines as an Ensign at the age of 14. He was promoted second lieutenant on 20 February 1771. He was serving aboard HMS Southampton when Queen Matilda of Denmark was dramatically rescued.
Collins went to North America early in 1775, and fought at the Battle of Bunker Hill, where the British suffered heavy casualties, but held the heights of Charlestown. He was promoted to first lieutenant the following week.
By November 1776, he was stationed at Halifax, Nova Scotia, where he met and then married Mary (Maria Stuart) Proctor, the daughter of Captain Charles Proctor, on 13 June 1777. He was promoted captain-lieutenant in August 1779, and outright captain by July 1780. In February 1781, he joined the HMS Courageux in the Channel Squadron, but did not enjoy being at sea.
In October 1786, after three years on half-pay stationed at Chatham, Collins volunteered for service in the proposed penal colony of New South Wales. On 29 November, and despite a lack of legal training, he was named Judge Advocate for the new colony and chief judge for a military court administering the New South Wales Marine Corps. In May 1787 he sailed aboard the First Fleet, reaching Sydney Cove in January 1788.
In June or July 1788, Governor Phillip appointed Collins as the Secretary to the Governor, or Secretary to the Colony as the position was sometimes called. Collins filled the three roles of Secretary, Judge Advocate and Lieutenant Governor until he left the colony for England in 1796.
Collins also established the first, short-lived settlement in what is now the state of Victoria at Sullivan Bay on Port Phillip in 1803. He sailed from England in April aboard HMS Calcutta, arriving at Port Phillip in October to found a penal colony. After landing at Sullivan Bay near present-day Sorrento, he sent First Lieutenant James Hingston Tuckey of the Calcutta to explore Port Phillip. Tuckey's report, and Collins' own dissatisfaction with the site chosen, prompted him to write to Governor King, seeking permission to remove the settlement. When King agreed, Collins decided to move the colony to the Derwent River, on the island of Van Diemen's Land (Tasmania). He arrived there in February 1804 on Ocean, and established what would become the town of Hobart.
Collins left no published account of his work as Lieutenant-Governor at Port Phillip, nor later as the founder of Hobart.
Collins has given his name to Collinsvale in Tasmania, Collins Street, Melbourne, Collins Parade, Sorrento (adjacent to the site of the failed settlement) and Collins Street, Hobart. At Exeter Grammar School, now known as Exeter School, where he was educated, there is a house named after him.
Collins was portrayed by David Dawson in the 2015 TV series Banished.