He played in the National Hockey League (NHL) for the Colorado Avalanche, St. Louis Blues, Washington Capitals, New York Rangers, Tampa Bay Lightning, Anaheim Ducks and Boston Bruins.

[9] After defeat in the Hockey East semi-finals to the University of Maine, on April 3, 2010, Shattenkirk (along with Colby Cohen) was signed to three-year, entry-level contract with the Colorado Avalanche.

[10] On April 5, 2010, Shattenkirk was signed to an amateur try-out contract with the Avalanche's American Hockey League (AHL) affiliate, the Lake Erie Monsters, to conclude the 2009–10 season.

[12] On November 4, 2010, Colorado recalled Shattenkirk from Lake Erie and made his NHL debut in a home game against the Vancouver Canucks that same day.

[14] Later that day, Shattenkirk made his home debut with the Blues at the Scottrade Center, recording an assist in a decisive 9–3 victory over the Anaheim Ducks.

[citation needed] On July 31, 2019, Shattenkirk's contract was bought out by the New York Rangers after a disappointing 2018–19 season when he registered just 2 goals and 28 points in 73 games.

[25] Returning back to the city where he played college hockey, Shattenkirk provided a veteran presence on Boston's young blue line.

[26] On March 30, 2024, Shattenkirk became an unlikely hero for the Bruins, scoring the game winning shootout goal in the fifth round, lifting them past his former team, the Washington Capitals.

His experience and leadership proved to be valuable to the Bruins before Game 7 of the series, when Shattenkirk made an inspiring speech to the team, who would go on to win 2–1 in overtime.

[30] Shattenkirk, entrenched in the US National Team Development Program, first represented the United States in the 2006 World U-17 Hockey Challenge, helping collect silver.

[36][37] Following the completion of his rookie NHL season, Shattenkirk was chosen in his first men's tournament to represent the United States at the 2011 World Championships in Slovakia.