The annual Macy’s Thanksgiving Day Parade has a lot to do with it. The parade started in 1924 as a way to promote the store’s Christmas sales. Over time, people began to think of Thanksgiving as the kickoff of the holiday shopping season.
In 1939, business leaders convinced President Franklin D. Roosevelt to move Thanksgiving to the third Thursday in November, making the shopping season longer. But that led to confusion, as many Americans had already made plans to celebrate a week later. In 1941, Congress moved the holiday to the fourth Thursday in November.