On January 18, 2008, the Panthers called up Matthias from Belleville.
In his second NHL game on January 19, 2008, he scored his first two goals, both against goaltender Brent Johnson of the Washington Capitals.

On March 4, 2014, Matthias was traded, along with goaltender Jacob Markström, to the Vancouver Canucks in exchange for goaltender Roberto Luongo and Steven Anthony.

On February 13, 2015, Matthias recorded his first career NHL hat-trick in a 5–2 Canucks win over the Boston Bruins.

Despite posting a career-high in goals (18) and points (27) during the 2014–15 season, the Canucks opted not to re-sign Matthias after the expiration of his contract, whereupon on July 6, 2015, he signed a one-year, $2.3 million deal with the Toronto Maple Leafs as an unrestricted free agent.
Following the signing, Matthias expressed via Twitter that he was a Maple Leafs fan growing up and that he "couldn't be happier to play for [his] hometown team."

In the 2015–16 season, Matthias made his Maple Leaf debut on opening night in a 3-1 defeat to the Montreal Canadiens on October 7, 2015.
Throughout the year, Matthias failed to score at a pace similar to his prior season in Vancouver, but was still seen as a decent producer given his role on the team.
After contributing with 17 points in 51 games, on February 21, 2016, Matthias was traded by the rebuilding Maple Leafs to the Colorado Avalanche in exchange for a 4th round pick in the 2016 Entry Draft and prospect Colin Smith.

On July 1, 2016, Matthias left the Avalanche organization as a free agent, agreeing to a two-year deal with Central division competitors, the Winnipeg Jets.
On January 18, 2008, the Panthers called up Matthias from Belleville. In his second NHL game on January 19, 2008, he scored his first two goals, both against goaltender Brent Johnson of the Washington Capitals.
On March 4, 2014, Matthias was traded, along with goaltender Jacob Markström, to the Vancouver Canucks in exchange for goaltender Roberto Luongo and Steven Anthony.
On February 13, 2015, Matthias recorded his first career NHL hat-trick in a 5–2 Canucks win over the Boston Bruins.
Despite posting a career-high in goals (18) and points (27) during the 2014–15 season, the Canucks opted not to re-sign Matthias after the expiration of his contract, whereupon on July 6, 2015, he signed a one-year, $2.3 million deal with the Toronto Maple Leafs as an unrestricted free agent. Following the signing, Matthias expressed via Twitter that he was a Maple Leafs fan growing up and that he "couldn't be happier to play for [his] hometown team."
In the 2015–16 season, Matthias made his Maple Leaf debut on opening night in a 3-1 defeat to the Montreal Canadiens on October 7, 2015. Throughout the year, Matthias failed to score at a pace similar to his prior season in Vancouver, but was still seen as a decent producer given his role on the team. After contributing with 17 points in 51 games, on February 21, 2016, Matthias was traded by the rebuilding Maple Leafs to the Colorado Avalanche in exchange for a 4th round pick in the 2016 Entry Draft and prospect Colin Smith.
On July 1, 2016, Matthias left the Avalanche organization as a free agent, agreeing to a two-year deal with Central division competitors, the Winnipeg Jets.
Shawn Matthias