He at first studied medicine but in 1805 was given a commission as an assistant surgeon in the Royal South Lincolnshire Militia as the threat from Napoleon increased.
Simmons spent the night before Waterloo sleeping on the muddy ground on a bundle of straw, sheltering from the rain under a mud-smeared blanket.
[2] He retired from the army in 1845, a Battalion Major, after thirty-six years' service, and died in St. Helier, Jersey on 5 March 1858.
[4][2] Soldier and author Willoughby Verner edited letters that Simmons wrote home during his service in the Peninsular and Waterloo Campaign to produce the 1899 work A British Rifle Man: The Journals and Correspondence of Major George Simmons, Rifle Brigade, During the Peninsular War and the Campaign of Waterloo.
Simmons married Anne Corbet, eldest daughter of Sir Thomas Le Breton of Bagatelle.