'Gronk', 29, made the announcement on social media on Sunday evening, having been contemplating his future since winning a third Super Bowl title in Atlanta in early February.
"It all started at 20 years old on stage at the NFL draft when my dream came true, and now here I am about to turn 30 in a few months with a decision I feel is the biggest of my life so far," he informed his 3.1 million Instagram followers. "I will be retiring from the game of football today.
"I am so grateful for the opportunity that Mr. Kraft and Coach Belichick gave to me when drafting my silliness in 2010. My life experiences over the last 9 years have been amazing both on and off the field."
Gronkowski added in a lengthy post that he wanted to "thank the whole New England Patriots organization for every opportunity I have been given and learning the great values of life that I can apply to mine".
Patriots head coach Bill Belichick said it had been a "pleasure and a privilege" to coach Gronkowski since he was selected out of Arizona in the second round of the NFL draft back in 2010, while owner Robert Kraft said he looked "forward to honoring him in the near future as both a Patriots and Pro Football Hall of Famer".
Four-time All-Pro Gronkowski played a total of 115 games for the Patriots - it would have been more not for a succession of injury problems - and caught 521 balls for 7,861 yards and 79 touchdowns, establishing a formidable connection with quarterback Tom Brady and winning Super Bowls in 2014, 2017 and 2019.
His 'Gronk Spike' became one of the most recognised celebrations in American sports.