Answer:
Franklin D. Roosevelt
Explanation:
When Franklin D. Roosevelt entered the White House, Thanksgiving was regularly celebrated each year on the last Thursday of November, but in 1939 the last Thursday in November fell on the last day of the month so, the President decided to move the holiday to the second to last Thursday of November to help the Christmas shopping season during the Great Depression. However, half of the states refused to accept the Presidential Proclamation and continued to celebrate it the last Thursday.
To set a fixed-date for the holiday, Congress passed a joint resolution in 1941 declaring the fourth Thursday in November to be the Federal Thanksgiving Day holiday and Roosevelt signed the resolution.
