A smart, smooth-skating defenseman, Hunwick has fashioned a solid career since entering the League with the Boston Bruins, who selected him in the seventh round (No. 224) of the 2004 NHL Draft.

Following four seasons at the University of Michigan, where he had 97 points (24 goals, 73 assists) in 163 games and served as captain as a senior, Hunwick spent most of his first professional season with Providence of the American Hockey League.

However, he made his NHL debut in a 2-1 win against the Buffalo Sabres on Nov. 10, 2007, and he recorded his first NHL point, an assist, in a 2-1 win against the Toronto Maple Leafs on Dec. 8, 2007. It was the only point he had in 13 games that season.

Although Hunwick again began with Providence in 2008-09, he stuck with Boston after making his season debut against the Montreal Canadiens on Oct. 15, 2008. He scored his first NHL goal in a 3-2 win against the Toronto Maple Leafs on Nov. 17, 2008, and finished with 27 points (six goals, 21 assists) in 53 games.

Hunwick made his Stanley Cup Playoff debut in Game 1 of the 2009 Eastern Conference First Round against the Montreal Canadiens, but he would miss the remainder of the postseason because of a ruptured spleen that required surgery.

On Nov. 29, 2010, Hunwick was acquired by the Colorado Avalanche for Colby Cohen. He played the next four seasons with Colorado and their AHL affiliate in Lake Erie before with the New York Rangers as a free agent on July 1, 2014.

In his one season in New York, Hunwick had 11 points (two goals, nine assists) in 55 games.

He signed as a free agent with Toronto on July 1, 2015, where he would play two seasons before signing with the Pittsburgh Penguins as a free agent on July 1, 2017.

However, after one season in Pittsburgh that saw him get 10 points (four goals, six assists) in 42 games, Hunwick was again on the move after being acquired in a trade by the Buffalo Sabres along with Conor Sheary on June 27, 2018, for a conditional pick in 2019 NHL Draft.