In January 1811 the 5lst joined Lord Wellington's army while encamped within the lines of Torres Vedras, and Elliott's first battle was Fuentes de Oñoro.

During the retreat from Burgos he acted as aide-de-camp to Colonel Mitchell, commanding the first brigade of the seventh division, and was wounded in conveying despatches under fire.

In that year his regiment was ordered for service in the Second Anglo-Burmese War, and Elliott was detailed to command the Madras brigade in the first campaign.

In the second campaign, which began in September 1852, Elliott again had command of a brigade, consisting of his own regiment and two battalions of Madras native infantry.

On 15 March 1831, at the church of All Souls, Langham Place in London, he married Jane Ashmore (1811–1879) but there is no record of any children.