Leake was the son of a master gunner, Richard Leake, who instructed him in mathematics and gunnery. He entered the navy when he was very young. In August 1673 he was at the battle of the Texel in the ‘Royal Prince’ in which his father was serving as master gunner. In 1689 he played the principal part in the relief of Londonderry while in the ‘Dartmouth'. He took part in the capture of Gibraltar in 1704 and remained in the Mediterranean in command of a squadron which defeated the Franco-Spanish attempts to retake the rock. Again in the Mediterranean he relieved Barcelona and captured Cartagena, Alicante, Ivisa and Majorca in 1706 and in 1708 Sardinia and Minorca, ensuring British supremacy. In 1709 he was appointed to the honorary post of rear-admiral of Great Britain, but declined the role of first lord of the Admiralty.