Fitzroy was commissioned into the
British Army in 1807 and fought in the 1809
Battle of Corunna of the
Peninsular War, before joining the
Walcheren Campaign the same year. He subsequently joined
Lord Hill's staff in Spain and was present at the
capture of Badajoz in 1812 and the battles of
Vittoria,
the Pyrenees,
Nivelle, the
Nive,
Orthez and
Toulouse serving as a Deputy Assistant Adjutant General (DAAG). At the
Battle of Waterloo in 1815, Fitzroy served on Wellington's staff as a captain in the
1st Regiment of Foot Guards and an Assistant Adjutant General (AAG). He then served on Wellington's staff in the army of occupation in Paris after Waterloo. His portrait was painted by
Edouard Pingret (who also painted a very similar portrait of Colonel
Dawson Kelly) in 1818 wearing the Waterloo medal on his AAG uniform. He retired from the army on
half pay as a major and
brevet lieutenant-colonel of the
27th Regiment of Foot in 1821. In retirement, he was chairman of the Finance Committee and honorary member of the 43rd
Middlesex Rifle Volunteers. ==Political career==