On April 14th, 1814, Williams joined the US Army, while in the midst of war with England. While the recruiter should not have allowed Williams to join because of his status, he was paid his full $50 bounty and got $8 a month in pay (the same as any private in the army). By the end of August, the British had sacked Washington DC and burned it to the ground. The American Army was in tatters, and the British set their sights on Baltimore. Williams and his regiment were deployed to Fort McHenry, where American forces waited for the British fleet. When the fleet arrived, it launched a land invasion while the fort was bombarded from two miles offshore. A cannonball took Williams's leg in the battle, and was taken to a Baltimore hospital. Meanwhile, with the British unable to take or destroy the fort (and the land invasion thwarted), the invasion fleet retreated from Baltimore Harbor. Williams died some two months later as the city and nation celebrated the heroics of Baltimore. He had made himself free in the same city that had lost him only 7 months later. Williams is one of only five fort defenders who lost their lives in the battle to defend our city, and we owe him and his fellow defenders our thanks. The flag that flew above the fort that night now rests in the Smithsonian as a national treasure.
While I can't provide confirmation, I heard a park ranger once mention that there's a possibility that Major George Armistead (who was given the flag after the battle) cut the star out of the flag to be buried with Williams. No documentation of where the star went exists, so the missing star still remains a mystery.
Check out the National Park website for more information on Williams, or visit Fort McHenry to learn more.