The ad was published two days after the Buccaneers signed Brady to a two-year contract.
Running under the headline "THANK YOU TOM," the Krafts' message praised Brady as "the GOAT and forever a part of our family."
"For 20 amazing years, you gave us everything you had," the ad reads. "When you arrived as a sixth-round pick -- and the best selection this franchise has ever made -- no one imagined all you'd accomplish or how much you'd soon mean to an entire region."
Brady, 42, left New England with six Super Bowl rings and 41 playoff starts since 2001.