He served as President of the Commission for the Sale of Lands in the Ceded Islands, and was appointed the first colonial governor to Dominica in 1770. Early in 1764, Prime Minister George Grenville nominated Young and he was appointed in the same year to be President of the Commission for the Sale of Lands in the Ceded Islands. The islands included Grenada, Tobago, Dominica, and Street Vincent, acquired from France as a result of the 1763 Peace of Paris.
In late 1764, he and his group sailed for Barbados, spending eight years away from his family during the period of 1764 to 1773, though in fact he made at least two return journeys in 1767 and 1770.
James Harris reports on attending concerts at Young"s residence in those years. The artist Agostino Brunias travelled with Young, recording Young"s progress and the visual context of his Commission"s work.
Young recorded "110 voyages of a like nature performed in the course of nine years amongst the ceded islands on the service of the Commission for the sale of lands." In 1768, Young was made Lieutenant Governor of Dominica and was chosen to be the first Governor of the new government, being sworn in on 17 November 1770. He was responsible for building the main military stronghold of Dominica in Roseau, Fort Young (now a hotel) in 1770 and for Government House, Dominica, his residence near the fort.
He left Dominica in 1772, rushing to Street Vincent to "assist with the Carib War" and to protect his estates there.
In 1769 he was made Baronet Young of North Dean. He was also a diarist and illustrator of works related to the Caribbean islands, although he hired Italian painter Brunias to paint pictures for him of the islands" people and interaction between the colonists and the natives, travelling with him through the islands. He was the author of Considerations which may tend to promote the settlement of our new West-India colonies: by encouraging individuals to embark in the undertaking (1764).
Young Island in the Grenadines is named in his honour.