On the 9th of September, 1813, he was gazetted as Ensign in the 39th Regiment of Foot.

He served with his regiment in the Pyrenees, and in a desultory campaign in Canada.

When Napoleon escaped from Elba, the 39th returned to Europe, but all too late to join in the victory of Waterloo, and it was stationed with the Army of Occupation in the north of France.
In 1818, the regiment was sent to Ireland.

Here for several years Sturt remained in most uncongenial surroundings, watching smugglers, seizing illicit stills, and assisting to quell a rising of the Whiteboys.

It was in Ireland that the devoted John Harris, his soldier-servant, who was afterwards the companion of his Australian wanderings, was first attached to him.