Brock would have preferred to fight in Europe against Napoleon but he was assigned instead to Upper Canada with his regiment, the 49th. Here he died and became a hero.

He was born in 1769 on Guernsey, the Channel Island then called Sarnia, a British possession off the coast of France. He was an exceptional youth, tall at over six feet, broad and muscular to go with the height. At fifteen, he joined the 8th Regiment of Foot as an ensign and later became a captain in the 49th. After serving with the regiment in the Caribbean, he bought the regiment commander's lieutenant colonel's commission. He then spent his energy revitalizing the regiment, turning it into one of the best regiments in the Army. In 1802, his regiment was ordered to Upper Canada.

In the next ten years, Brock worked to improve the state of the military in Canada. He was convinced that war between Britain and the US would occur soon and his opinion of the preparedness of the military was not high. Brock built and repaired military fortifications, trained the militia, and generally prepared Canada for the war that he regarded as inevitable.

In 1811, he was promoted to major general and took control of all troops in Upper Canada. When the Lt. Governor of Upper Canada, Francis Gore, returned to England temporarily, Brock became the administrator in his absence. This was the situation when the United States declared war in 1812.

The Commander-in-Chief in Canada was Sir George Prevost, the Governor-General, who was more a cautious politician than military man. Prevost was of the opinion that Canada only had enough forces to defend Quebec, and so he wanted Brock to defend Upper Canada and conserve his forces. Brock's view was that the best way to cover up a weak defence was to attack, so, against the wishes of Prevost, he attacked and took Fort Mackinac, near Sault Ste Marie. When the Americans attacked Sandwich, now part of Windsor, he typically took that as an excuse to override Prevost's caution again. He allied himself with the leader of the native forces, Tecumseh, and attacked Detroit, forcing the surrender of the American general, William Hull, and 2000 of his men. When Tecumseh heard of Brock's intention to attack Detroit, he said, "Now here is a man!"

Prevost, however, stopped Brock's momentum by signing an armistice with the American commander, Henry Dearborn. This allowed the Americans some breathing space, which they used to build up their forces around Niagara. American general Stephen Van Rensselaer attacked at Queenston and Brock was killed at the Battle of Queenston Heights. He had received a knighthood only a few days before his death but never knew of the award.