He was selected 2nd overall by the Mighty Ducks of Anaheim in the 1994 NHL entry draft, playing 713 games in the National Hockey League (NHL) with the Mighty Ducks of Anaheim, Winnipeg Jets, Phoenix Coyotes, New Jersey Devils, Carolina Hurricanes, and Los Angeles Kings.

Due to the 1994–95 lockout delaying the season, Tverdovsky was assigned to the Brandon Wheat Kings of the Western Hockey League, where he played seven games.

When he debuted for the Mighty Ducks, he set a franchise record for being the youngest player to suit up for a game, at 18 years, eight months and 13 days.

[4] While establishing himself as a fixture on the Coyotes blueline for his tenure with the club, Tverdovsky was traded back to the Mighty Ducks at the 1999 NHL Entry Draft in exchange for Travis Green and a 1999 first-round pick (Scott Kelman).

[6] On 29 September 2006, Tverdovsky and Jack Johnson were traded to the Los Angeles Kings in exchange for Éric Bélanger and Tim Gleason.