"This is a very, very good team ... I need to win a Stanley Cup and I think this a great team that could do that," the 41-year-old told reporters during media avail.
Thornton, a product of London, Ont., joined the Maple Leafs on a one-year, league-minimum deal worth $700,000 earlier this week after spending the last 15 seasons with the San Jose Sharks. Despite having 179 playoff games under his belt and making the post-season in 17 of his 22 seasons, including a run to the final with the Sharks in 2015-16, Thornton has never tasted Cup glory.
It's a result he's hoping will change in Toronto - even though the Leafs have not won a playoff series since 2004 - in part because of their No. 1 netminder.
"I love their goalie. I really, really do. I like (Frederik Andersen) I think that was a big part of my decision here. I think he's a great goalie," said Thornton.
"I think up the middle they're very, very strong; I think adding TJ Brodie on the backend really solidifies their D, Zach Bogosian coming in, Wayne Simmonds; but, you know, the Auston Matthews, the Mitch Marners, the John Tavares, the (William) Nylanders, the list goes on and on and on, Zach Hyman, Morgan Rielly -- this is a really, really good team and I think it's going to be a great team at end of this."
But to leave San Jose - which he's called home since he was sent to the Sharks in a blockbuster deal from the Boston Bruins when he was a 26-year-old -- was an achingly tough call.
"It was probably the hardest hockey decision that I've ever had to make," he said.
So difficult, in fact, that he sought the advice of another Bay-area legend: Joe Montana, who won four Super Bowls across 13 years with the San Francisco 49ers before joining the Kansas City Chiefs to end his career.