He was born in 1730, the youngest son of John Sawyer of Hayward, Berkshire by Anne, sister of Anthony Duncombe, Lord Feversham.

He was promoted to lieutenant on 4 March 1756, and the following year was serving aboard HMS Grafton, which at the time was part of Vice-Admiral Francis Holburne's fleet off Louisbourg.

On 21 May 1762 he and the sloop HMS Favourite, the latter commanded by Philemon Pownoll, captured the Spanish treasure ship Hermione off Cadiz.

Sawyer remained in the Caribbean, and was present at the Battle of Grenada as part of Vice-Admiral John Byron's fleet on 6 July 1779.

[1] He took up his post in June, and authorized the frigate HMS Mercury to escort a merchant vessel to the American port of Boston to collect a shipment of cattle.

[1] In 1787 Sawyer had taken part of his fleet to Quebec, where he was embarrassed by a French squadron of three ships of the line and four frigates, which sailed unchallenged along the Nova Scotia coast bound for Boston.