During his career during he won a record seven Super Bowl championships.

The 44-year-old Brady spent 20 seasons with the New England Patriots, winning six Super Bowl titles, before relocating to Tampa Bay and leading the Bucs to a championship last season.

"I have always believed the sport of football is an 'all-in' proposition - if a 100% competitive commitment isn't there, you won't succeed, and success is what I love so much about our game," Brady wrote on Twitter on Tuesday.

"There is a physical, mental, and emotional challenge EVERY single day that has allowed me to maximize my highest potential. And I have tried my very best these past 22 years. There are no shortcuts to success on the field or in life.

"This is difficult for me to write, but here it goes: I am not going to make that competitive commitment anymore. I have loved my NFL career, and now it is time to focus my time and energy on other things that require my attention."

Brady added: "My playing career has been such a thrilling ride, beyond my imagination, and full of ups and downs. When you're in it every day, you really don't think about any kind of ending.

"As I sit here now, however, I think of all the great players and coaches I was privileged to pay with and against. The competition was fierce and deep, just how we like it. But the friendships and relationships are just as fierce and just as deep.

"I will remember and cherish these memories and visit them often. I feel like the luckiest person in the world."

Brady said "the future is exciting" and pointed to personal and business ventures that have his interest, but his primary focus becomes "my greatest achievement," which he said was his family.

Brady's decision follows a dominant season during which he led the NFL in touchdown passes and passing yards. He could win a fourth league Most Valuable Player trophy, which would make him the oldest player to win the award.

Australian Associated Press