Between 1798 and 1812 he served in the Mediterranean fleet, first as a midshipman, during which service he was cited for “conspicuous bravery” at the siege of Acre (‘Akko, Israel) in 1799. On 27 Dec. 1805 he was promoted lieutenant and during the battle of Málaga, in 1812, he led a party which captured French shore batteries and a privateer.

In the spring of 1813 he and his father were among those sent to North America to reinforce the British fleet on the Great Lakes. Following his arrival in Kingston, Upper Canada, Spilsbury Jr was promoted commander on 8 March 1813 and took command of the armed schooner General Beresford. In May he was part of Commodore Sir James Lucas Yeo*’s squadron on Lake Ontario which raided Sackets Harbor, N.Y., and in June Spilsbury’s detachment captured the American shore batteries and stores at Forty Mile Creek, in the Niagara peninsula. On 11 September he commanded the brig Lord Melville during an engagement off the Genesee River and though his ship was hit below the water-line his skilful action allowed repairs to be made during the battle. He was also present at the actions off Burlington Bay (Hamilton Harbour) on 28 September and French Creek, N.Y., on 1 November. In the campaign of 1814 he commanded the ship Niagara; shortly after the successful attack on Oswego, N.Y., on 6 May, Spilsbury was taken prisoner during the bungled advance up nearby Sandy Creek and was later confined at Cheshire, Mass., until the end of hostilities.

Following the peace in 1815, Spilsbury was promoted post captain on 19 September and was soon retired on half pay.