Hamrlik was a mainstay on the Lightning defense for five-and-a-half years before being traded to the Edmonton Oilers as part of a five-player deal on December 30, 1997. In 1998 he was part of the Olympic gold medal winning Czech Republic team, which defeated Russia in the final and was one of the top performers throughout the tournament.

Although Hamrlik played well with the Oilers, he was traded to the New York Islanders in the summer of 2000 and along with the likes of Michael Peca was an instrumental force in getting the Islanders back into the postseason in 2002, while suiting for his native homeland at the 2002 Winter Olympics in Salt Lake City.

Following four seasons on Long Island, Hamrlik was acquired by the Calgary Flames in the summer of 2005. In Calgary Hamrlik would compete in 126 games over two seasons and continue to establish himself as a solid NHL veteran. His stint in Calgary would come to an end in the summer of 2007 as the Montreal Canadiens signed the free agent defenseman to a four-year contract through to 2010-11.

After four solid seasons on the Canadiens blue line, Hamrlik found himself once again an unrestricted free agent. On July 1, 2011 he inked a deal with the powerful Washington Capitals.

Hamrlik credits his brother Martin as having the most influence on his hockey development while growing up in the Czech Republic. The two played together for several years on the national team. He also says Phil Esposito and former Tampa Bay coach Wayne Cashman both gave him the confidence to play in the NHL and says he will always be grateful to them both for that.