On the field, Gronkowski is all business, except when he spikes the ball after scoring. He understands the offense, runs precise routes and makes complex adjustments in a split-second.
Off the field, he's a happy-go-lucky 22-year-old whom punter Zoltan Mesko calls "hilarious" and linebacker Rob Ninkovich describes as "a free spirit" who gets along with everyone.
"I guess he says it best," Ninkovich said. "I think he refers to himself as a beast all the time. 'I'm a beast.' So I think that when he gets on the field he obviously puts himself in a different mindset and does his beasting the best on the field. Everybody says that they're different on the field and you can see that with a lot of guys."
Sometimes, Gronkowski's carefree off-field persona can lead to trouble.
During the Patriots' bye week after their sixth game, adult film performer BiBi Jones posted two pictures of her with Gronkowski on her Twitter account. She was wearing his Patriots jersey in both. In one, he was shirtless.
He met with team owner Robert Kraft and apologized publicly, saying being in the pros is a learning process and "I didn't intend anything to hurt the reputation of anyone on the New England Patriots."
Since then, he's stuck with the team-first approach that Belichick emphasizes, often answering questions about his success by crediting teammates.
"It's unbelievable," Gronkowski said after the win over the Ravens put the Patriots in their fifth Super Bowl in 11 years. "It's my second year in the league, playing with a great team, and you have to enjoy the moment. It doesn't even feel right, especially playing with the veterans here. I watched them go to the Super Bowl as I was growing up and now I'm part of it? It is an unreal moment and you can't take it for granted."