With the outbreak of war with the American colonies, MacBride was appointed to take command of the 64-gun on 6 November 1776. He was present at the Battle of Ushant on 28 July 1778, but did not become heavily engaged in the confused action. In the ensuing argument over the outcome of the battle, MacBride gave evidence in favour of Admiral Keppel that was an important factor in Keppel's acquittal at his court-martial. MacBride was less supportive of Sir Hugh Palliser. He remained in command of "Bienfaisant", and in December joined Sir George Rodney's fleet to relieve Gibraltar. During the voyage the British fleet came across a Spanish convoy transporting naval stores from San Sebastián to Cádiz, and engaged it. The British succeeded in capturing the convoy, while MacBride distinguished himself in engaging the Spanish flagship "Guipuscoana", which surrendered to him.