Studied law Middle Temple, London, England. Led expedition
In May 1746, he went out as agent of a company for the discovery of the Northwest Passage. After extinguishing with difficulty a fire in his ship, he sailed to Greenland, where he exchanged commodities with the Inuit peoples on 8 July. He then proceeded to Fort Nelson, and wintered in Hayes River.
He renewed his efforts in June 1747, without success, and returned to England.
Where he arrived on 14 October. He published an accounts of his explorations in 1748, entitled "Voyage made to Hudson"s Bay in 1746, by the Dobbs Galley and The California, to discover a Northwest Passage" and in 1750 published "Considerations relating to the Northwest Passage".
After publishing these accounts, Ellis was inducted into the Royal Society. From 1750 to 1755, Ellis worked as a slave trader, purchasing slaves from Africa and shipping them to Jamaica.
Lord Halifax, President of the Board of Trade named Ellis lieutenant governor of Georgia, 15 August 1756.
Ellis arrived at Savannah, Georgia on 16 February 1757, and on 17 May 1758, was made royal governor. His administration of the colony was highly esteemed. Recognizing the danger posed to the colony by hostile neighbors, he established a treaty with the Creeks.
He published "Heat of the Weather in Georgia" in Philosophical transport of the Royal Society in 1758.
The subtropical climate took its toll on his health, and he had to be removed from governor then left Georgia on 2 November 1760,and stopping in New York to request military assistance to the southern colonies. After his return to England his knowledge of American affairs were called into requisition for developing the plan for taxing the colonies, and in return for this service he was rewarded with sinecure offices.
From 1761 to 1763 he held the commission of governor of Nova Scotia, though he did not enter on the duties of his office. He afterward resided in Italy, principally occupied in scientific researches.
He died on January 21, 1806(1806-1801-21) (aged 84–85) in Naples, Italy.
Namesake of Fort Ellis (Nova Scotia), which Fort Ellis Road is named after.