He went to Harrow at nine, was commissioned in the Horse Guards at sixteen and served at Waterloo. At thirty-seven he retired from the army and, at forty-one years of age in 1837, was appointed Lieutenant-Governor of Prince Edward Island. His next appointment, in 1841, was Lieutenant-Governor of Leeward Islands. In 1845 he became Governor of New South Wales replacing Sir George Gipps. 
On 2nd August 1846 HMS Carysfort arrived in Sydney bringing the new governor. He was accompanied by his wife, Lady Mary Lennox, and his son George who became his private secretary. As early as 9th November 1846 he set off with his wife and son on the first of what 
were to be many journeys into the rural districts. They crossed the Blue Mountains to go as far as Carcoar and Molong, Fitzroy driving his own four-in-hand much of the way. 
After a most successful beginning of his governorship, tragedy struck on the 7th November 1847 with a carriage accident in the grounds of Government House at Parramatta, in which his wife as well as his aide-de-camp died. Fitzroy, who had again been driving, suffered severe leg injuries; consequently he considered giving up his post, but financial problems prevented this. Earlier in 1847, Earl Grey, the secretary of state, had written proposing to separate the Port Phillip District from New South Wales to form a new state, Victoria. 
And so it was that in 1851, despite his temptation to the contrary only little over three years previously, Fitzroy---then governor of New South Wales, van Diemen's Land, South Australia, and Victoria, and Governor-General of all the Australian possessions, including Western Australia---asked to have his governorship extended for another six years. By then, apart from his son George still as private secretary, he had been joined by his eldest son, Captain Augustus Charles, who became his civil aide-de-camp, and by his only daughter, Mary Caroline, the Hon. Mrs. Keith Stewart, who acted as his hostess. 
In early 1855, Fitzroy was replaced by Sir William Denison and, returned to London and, on 11th December 1855, married Margaret Gordon, widow of a Melbourne land-agent. He died at the age of sixty-two in Piccadilly on 16th February 1858.

Source: Leo van de Pas