In 1963, John F. Kennedy became the first president to publicly let his Thanksgiving turkey go free.
He didn't use the word "pardon", but his family didn't eat the lucky bird for Thanksgiving.
He actually said, "Let's just keep him."
The next day the newspapers printed headlines that said "Kennedy Pardoned Turkey".
And thus began a new tradition of presidential turkey pardons.
President Kennedy Pardons Turkey-1963