Brock was born on the Channel Island of Guernsey.

In the early phase of the war, he, along with the Native American chief, Tecumseh, were responsible for many of the early victories for the British forces against the American invaders. His diplomatic efforts also ensured that the regional Native American nations stayed allied to the British, especially in fostering good relations with Tecumseh.

His capture of Fort Detroit was particularly impressive. He instructed to the Native American warriors to make as much noise as possible, which frightened Brigadier-General William Hull into surrendering even though he had superior forces.

He was killed at the Battle of Queenston Heights on October 13, 1812.

Although he had little regard for the Canadian colonies, he was and is regarded in Canada as a hero who managed to frustrate the American invaders when all seemed hopeless for the colonies. The tributes to him include a memorial on Queenston Heights, a city named after him called Brockville, and a university, Brock University.