In 1813, at the age of 64, Whitley returned to military service. He volunteered in the Kentucky Mounted Infantry during the War of 1812 with Great Britain. In the Battle of the Thames, on October 5, 1813, he led the "Forlorn Hope" charge against Tecumseh's forces. Both Tecumseh and Whitley were killed in the battle. Whitley was buried near the battleground, in Chatham, Ontario. Militia colleagues returned his horse, Emperor, his powder horn, strap, and rifle to his wife in Kentucky after the war. The rifle is currently on display at the William Whitley House State Historic Site.