Clark played four years for the Clarkson Golden Knights in the ECAC (NCAA Division I), recording 128 points (63 goals and 65 assists) and 392 penalty minutes in 142 games.

On December 28, 2009, Clark (along with defenseman Milan Jurčina) was traded to the Columbus Blue Jackets in exchange for winger Jason Chimera.

[4] Clark was the third-longest tenured captain in the history of the Washington Capitals, behind only Hockey Hall of Famer Rod Langway and Dale Hunter.

[9] After he was released by Providence, Clark took up a scouting position with the Columbus Blue Jackets organization for the remainder of the 2011–12 season before being named the team's development coach.

In 2007, Clark was chosen as the captain of the United States national team for the 2007 IIHF World Championship, where he scored two goals and one assist in six games.