Boyle succeeded his paternal grandfather as 2nd Viscount Shannon of the Peerage of Ireland in 1699. He became colonel of Prince George of Denmark's Regiment of Marines in February 1702 and commanded a brigade of grenadiers during the storming of Vigo in October 1702 during the War of the Spanish Succession. During this engagement the entire French fleet, under the command of the Marquis de Château-Renault, together with the Spanish galleons and transports under Manuel de Velasco, were either been captured or destroyed. For his good conduct at Vigo, Boyle was sent home to present the despatches, which reported on the destruction of the French fleet, to Queen Anne. She rewarded him with a gratuity of £1,000. However, in January 1703 he was accused of being involved in some scandalous activity at St James's Church, Piccadilly.