In his later career Smith was involved in expanding the British Empire in the West Indies by protecting its trade routes, helped keep control of the islands of Gibraltar and Madeira and commanded various artillery regiments.
His first wife, Mary Leigh, died in childbirth, and he married second Grace Weatherall at Chatham, Kent on 17 April 1782, with whom he had five children in total.
In 1778 he served under General Sir Henry Clinton during the withdrawal to New York and saw further combat at the Battle of Monmouth.
[2] With the start of the French Revolutionary Wars, Smith was appointed second in command of the artillery intended to accompany Lord Moira's expedition to France.
Command of all thirteen companies of the Royal Artillery serving in the West Indies then fell to him, and on 27 August 1797 he was promoted to lieutenant-colonel.
[2] In September and October 1799 Smith commanded the artillery during the Duke of York's Anglo-Russian invasion of Holland.
On 3 July 1815 he was appointed colonel-commandant of the 7th Battalion, Royal Horse Artillery, was promoted to lieutenant-general in 1819, and received the Grand Cross of the Hanoverian Guelphic Order being knighted on 10 August 1831.