He wasn't yet a Bostonian. He was fresh off signing a three-year deal with the Spoked-B as an unrestricted free agent. He had just won the Stanley Cup with Anaheim.
On that first trip, he made a community appearance and hosted a kids' street hockey clinic at the YMCA in Franklin, Massachusetts. He didn't leave Boston without taking a trip to Fenway Park to watch the Red Sox take on the Orioles.
By the time he left, and before he even laced up his skates for the 2007-08 season, he was a Bostonian.
General Manager Peter Chiarelli had acquired him as a step in making the Bruins tougher, and harder to play against.
"He's a thick, physical player," the GM said on the day of the signing. "He's earned everything he's gotten."
"I'm trying to strive and get some vigorous [players] and he is going to help us in that regard."
In Thornton's first season, he found his way into the hearts of the Boston faithful, working hard and providing energy for the Black & Gold every night.
On and off the ice, he appreciated the organization and the community - and they appreciated him right back.
Now, seven years later, the Bostonian in Thornton will never leave him. But the 36-year-old will be finding a new NHL home for the 2014-15 season.
On June 16, Chiarelli met with the forward to discuss his future. Thornton will become an unrestricted free agent on July 1.
"I met with Shawn, and we had a good meeting, and I informed him that we wouldn't be re-signing him," the GM told BostonBruins.com following the meeting.
The pair talked about Thornton's time in Boston, when he arrived seven years ago, just one season after Chiarelli's own arrival to Boston.
"He was here from almost the beginning, and I told him that he was one of the most significant acquisitions we made," said Chiarelli.
"One, for the role that he played. Two, for the person that he is."
Throughout his time in Boston, Thornton punished opponents with his fists and fooled them at times with his silky (and unexpected) moves. He protected and stood up for teammates. He ingrained himself in the team's culture, never hesitating to be a leader when focus - or an extra spark - was needed.
"I thought when he came here, I think his conditioning really went to the next level and he was able to form one third of maybe the best fourth line in hockey for the longest time," said Chiarelli.
"Of course, there's the pugilistic component of his game, which is an important part and he was very good about that, and that it was a job that not a lot of people like to do, but it was a job that was important."
"He came, and he thrived and was really a common factor in every year, he contributed, he scored some timely goals, he's got some surprising skill for what role he brings and of course, he won a Cup with us and went to the Final again."
As equally tough as he was on the ice, he was gracious, amiable and charismatic off the ice, never hesitating to get involved with charitable efforts around the Boston community. Eventually, he took over the team's annual "Cuts for a Cause" event every spring, and in 2013, he launched the Shawn Thornton Foundation.
"I see him doing a lot for charitable organizations - he enjoys it, he embraces it, he's a very personable and very genuine guy," said Chiarelli.
"So, he'll be missed. It's a bit of a sad day. But, you know, I think Shawn was good, he embraced the time that he was here, and that's how we look at it."
During the Bruins' final day of media availability of the 2013-14 season on May 16, Thornton not surprisingly voiced that he hoped he would be remaining in Black & Gold. But he understands the business aspect of it, and he knew his return could go either way.
For Chiarelli and the Bruins' brass, they must always be 'unemotional' when dissecting the organization, from top to bottom. While emotions undoubtedly come into play, like in the case of a seven-year relationship with a player, they continually weigh all options and view all circumstances. That's the business of it.
"You know, it was nice to rehash his time, it was sad to tell him that he wasn't coming back, but I wished him well," said Chiarelli. "And Shawn was real up-front about it, so I wished him luck, and I'm sure he'll have success with his next team."
Before we wish him all the best, let's do some rehashing of Thornton's time with Boston, which, according to him, will never truly come to an end.
In 2007, Thornton had one Stanley Cup ring. Now, he has two. The veteran of 559 NHL games (with 38 goals and 50 assists) has logged 906 career penalty minutes. He played 480 games as a Bruin, notching 34 goals and 42 assists, with 748 penalty minutes. He logged 102 total fights, lighting the fire of the Garden crowd on countless occasions.
The first 15 playoff games of his career were played en route to the Cup with Anaheim. The next 86 were spent trying to bring the Cup back to Boston. In 2011, with the famous 'Merlot Line,' Thornton and the Bruins ended the 39-year drought.
He will certainly be missed by his linemates, Daniel Paille and Gregory Campbell.
"After the season ends like that and you don't win, you always think about certain things like that - you reflect on it and do realize that it's a business and people do tend to move around at times," Paille acknowledged during the team's breakup day for the 2013-14 season on May 16.
"And I think we're all professional and capable and ready to do that if that happens."
Asked about the impact Thornton has had, Paille was quick to share.
"He's been a tremendous supporter of the community. He's very known to help out around everywhere in Boston, and as a linemate, we've played together for a number of years, and it was just such a thrill to play with him," said Paille.
While Thornton, Paille and Campbell solidified the 'Merlot Line' the past few years, always donning their merlot-colored practice jerseys, Brad Marchand knows a thing or two about the hard-working 'merlot mentality.'
When Marchand first joined the team full-time, he was on the fourth line with Thornton, wearing that same merlot jersey. One day, he went out and bought velour burgundy-colored jackets for the trio. Campbell still admits to having his; I'd bet Thornton has his stashed somewhere as well.
"He made it very easy for me, coming into the League and being on his line," Marchand said on break-up day. "[I've] got a lot of respect for Thorty."
When Thornton came to Boston, it also marked Milan Lucic's first full-time season in the League.
"Me and him, when I started here, he started here as well, establishing himself as the guy that he is in Boston," Lucic said. "We’ve had a great relationship over the last seven years, you see those posters, the ‘Bruise Brothers,’ that kind of stuff. Early on, we were playing together on the same line, and we really fed off one another."
With the departure of Thornton, a strong core of Bruins led by Zdeno Chara, Patrice Bergeron, Tuukka Rask, David Krejci and Lucic still remains. He will be missed. There's no doubting, or denying that. His impact on that core, and the rest of the Bruins still in Boston, will be certainly felt for years to come.
While he won't be in the Black & Gold next season, the Bostonian in him will always be part of the fabric of this city and for that, Bruins fans will be forever grateful.
"I am still going to be here. This is where we live now. This is home. That stuff will not change," Thornton said to media back on May 16, when the 2013-14 Bruins convened for the final time. "I’ll be here, trying to give back when I can. I love it here."
"I love it here, I really do. There's a reason that we stick around in the offseason. It's one of the best cities in the world. I can't think of anywhere else I would have rather been."
'And you'll go down as one of the greatest Bruins,' a reporter had chimed in.
"Ever. In the history of the world," Thornton had laughed, as media began to dissipate, with no further questions for him. "How's that for an ending?"