At 37, Thornton is the graybeard of Team Canada, very literally in his case with strands of gray hair slowly taking over the center's big, bushy beard.
But despite his venerable status, the first thing anyone mentions when talking about Thornton is how happy he is, how he keeps players loose and loves joking around. It is a personality trait that tends to fade with age, but in Thornton's case, it is the opposite.
"I've been really good at just staying in the moment, I think that's what's [allowed] me to play so long," he said. "I just love coming to the rink every day, I love seeing the guys. I still feel like I'm 24."
The last time Thornton wore the Canada sweater was at the 2010 Vancouver OIympics, winning a gold medal alongside current teammates Sidney Crosby, Patrice Bergeron, Jonathan Toews, Ryan Getzlaf, Corey Perry, Drew Doughty and Shea Weber.
"He hasn't changed," Crosby said. "He's a pretty easygoing guy, he likes to have fun, and he's got a ton of experience. He's played a long time. He keeps things pretty loose."
His Sharks teammates couldn't be happier for Thornton, largely because of how much respect he has earned as one of their leaders.
When Team Canada forward Logan Couture was asked to describe what Thornton was like as a teammate, his answer was immediate, and very telling.
"The best," Couture said. "I think he's the best teammate I've ever had. He's a leader, a guy everyone looks up to in our dressing room in San Jose. You enjoy spending time around him, he enjoys playing the game. So yeah, he's the best teammate."
Thornton said it didn't really bother him that he wasn't in much of the public conversation for Team Canada because he wasn't thinking about it, and that's not really his style. If he worried about what people said about him, Thornton probably would spend a lot of time worrying.
His play in the Stanley Cup Playoffs over the course of his career has been one of the biggest sources of criticism, but Thornton has put together what should one day become a Hockey Hall of Fame career in the relative anonymity of San Jose, at least when compared to the intense glare of the spotlight he began his NHL career under with the Boston Bruins.
Thornton doesn't care what people say or think about him. He just goes out and plays hockey, and does it extremely well.
"He's always happy and in a good mood," Sharks and Team Canada defenseman Marc-Edouard Vlasic said. "Nothing bothers him. Nothing."
Thornton was passed over for the 2014 Sochi Olympics and, considering his age, would have been forgiven if he thought his international career had come to an end.
But Thornton was fourth in NHL scoring last season with 82 points in 82 games and was instrumental in helping the Sharks eliminate Armstrong's St. Louis Blues from the playoffs in the Western Conference Final.
Thornton had seven points in the final four games of the series, with the last game being played two days before the final Team Canada roster was named.
Coach Mike Babcock suggested Tuesday that playoff performance was a big reason Thornton made the team. He left them with no choice.
"Players earn their way here, and they do it by impressing good hockey men," Babcock said.
Thornton is one of 14 players participating in the 2016 World Cup who also played in the 2004 edition, the last time the event was held. He recalled how much he appreciated winning the tournament alongside players like Mario Lemieux and Joe Sakic.
When it was mentioned to him that Lemieux and Sakic are now in NHL management, Thornton chuckled.
"Yeah, and I'm still here," he said. "I've still got another 10 years, so maybe the next World Cup I'll play in it too."
