After being drafted by the Detroit Red Wings in the 2000 NHL Entry Draft, Kopecký played two seasons of junior hockey with the Lethbridge Hurricanes of the Western Hockey League. He turned professional with the American Hockey League, initially with the Cincinnati Mighty Ducks before being assigned to the Grand Rapids Griffins. Kopecký played four seasons with the Griffins before making his NHL debut with the Red Wings in 2005–06, appearing in one game. The following season, on December 14, 2006, in a game against the Chicago Blackhawks, Kopecký was injured a minute into the third period of the Red Wings' 3–2 victory. Kopecký lost his footing and hit the boards as he approached the Chicago blue line and Blackhawks defenseman Jim Vandermeer then fell on top of him. Kopecký was motionless on the ice for a few minutes before being helped to the dressing room by members of the Detroit training staff. He had surgery the next day to repair a broken clavicle. As a result of this injury, he was limited to just 26 games in 2006–07 season. Kopecký had previously worn the number 28 with Detroit, but switched to 82 after the Red Wings acquired free agent defenseman Brian Rafalski. On April 3, 2008, near the end of the 2007–08 season, Kopecký tore his Anterior cruciate ligament during a game against the Columbus Blue Jackets. This injury was repaired during surgery on April 22, 2008. On June 4, 2008, he won the Stanley Cup with the Red Wings, though he did not play a game in the post-season.
Chicago Blackhawks
On July 1, 2009, Kopecký signed a two-year deal with the Chicago Blackhawks worth $1.2 million per season. He played in 74 games for the Blackhawks in his first year with the team, posting 21 points, 28 penalties-in-minutes, two game-winning goals and a shooting percentage of 10.5%. Into the post-season, Kopecký was a regular starter on Chicago's third or fourth forward lines. He scored a crucial goal to put Chicago up by two in the Western Semifinals against the Vancouver Canucks, but his most crucial would be in his first game back in the lineup after being a healthy scratch for all four games of the sweep of the San Jose Sharks. Replacing the injured Andrew Ladd, Kopecký netted the 6–5 game-winning goal in the Game 1 victory of the 2010 Stanley Cup Finals. Ladd returned the next game, but Blackhawks Head CoachJoel Quenneville kept Kopecký in the lineup to play every game of the six-game series. He finished the playoffs with solid statistics; in 17 games, he tallied six points, 8 PIM, one game-winning goal and a shooting percentage of 14.3%. On June 9, 2010, at the age of 28, he won the Stanley Cup with the Blackhawks and hoisted the Cup for the second time in his life. Kopecký entered the 2010–11 season in the last year of his contract with the defending champion Blackhawks. He opened the first game of the year on the team's first line with Jonathan Toews and Marián Hossa, putting in over twice the amount of time on the ice that he had averaged the year before. On December 26, 2010, in his 36th game of the year, Kopecký tallied his 21st point of the season, matching his career high total for a single season. Kopecký played in the Blackhawks' last game of the season on April 10, 2011, against his former team the Red Wings. Chicago needed a win to decisively clinch a playoff spot. The Hawks lost the game 4–3, but still clinched the eighth seed of the playoffs due to a Dallas Stars loss on the same day. Kopecký ended the season with career highs in games played, goals, assists, points, shots and PIM, and had now been on a playoff-bound team for five consecutive seasons. Kopecký was taken out of Game 1 with an upper-body injury of the Blackhawks' first playoff series against the Vancouver Canucks. He did not return to the ice for the rest of the series, and the Blackhawks ultimately lost the first-round matchup in seven games.
Florida Panthers
Following the 2010–11 season, Kopecký was poised to become an unrestricted free agent on July 1, 2011. However, on June 27, the Blackhawks traded Kopecký to the Florida Panthers, who obtained the exclusive negotiating rights with the player until he was to become a free agent. In return, the Blackhawks received a seventh round draft pick in either the 2012 or 2013 NHL Entry Draft. Two days later, on June 29, the Panthers signed Kopecký to a four-year deal worth a total of $12 million. At the conclusion of his contract with the Panthers, and failing to meet the expectations of his contract, Kopecký went un-signed over the summer as a free agent. On October 22, 2015, Kopecký returned to Europe and signed in the Czech Republic for the remainder of the season with HC Oceláři Třinec.
Personal life
Tomas is married to Maria and has two sons named Jakub and Tobias.
International play
Kopecký has participated in eight international tournaments for Slovakia:
