Unsigned by the Capitals, Barch signed as a free agent with the Dallas Stars on July 18, 2006. Barch made his NHL debut in the 2006–07 season on January 15, 2007 against the Los Angeles Kings after being called up due to injuries. He remained with the Stars for the remainder of the season, played in 26 of 37 games and scored 3 goals and 2 assists for 5 points. Known as a hard-hitter, Barch had 107 penalty minutes, which included 13 fighting majors.
On December 7, 2011, the Dallas Stars traded Barch and a 6th-round pick in the 2012 draft, to the Florida Panthers in exchange for the minor league forward Jake Hauswirth and a 5th-round pick in 2012.
On December 31, 2011, in a game against the Montreal Canadiens, Barch was given a game misconduct penalty at the end of the first period, following an incident between teammate Erik Gudbranson and P.K. Subban. Hockey Night in Canada on CBC reported that the ejection was due to Barch making what was deemed to be a racial slur against Subban, who is of Jamaican descent. The incident was witnessed by linesman Darren Gibbs who was standing in front of the players' benches. Barch was suspended one game by the NHL for his comment.
Barch signed a two year contract with the New Jersey Devils on July 5, 2012.
On September 28, 2013, Barch was traded with a 7th round pick to Florida for a 6th round pick and Scott Timmins.
Krys and his wife Holly have 3 children: son Hayden, born April 14, 2007, son Kane and a third son.