Hardy was born in Switzerland where his father was playing professional hockey before moving to Montreal as a child. He played four seasons of junior in the Quebec Major Junior Hockey League for the Montreal Juniors and was selected 30th overall by the Los Angeles Kings at the 1979 NHL Entry Draft. Hardy is ranked 3rd in all-time scoring by an LA Kings defenseman. He played 915 career NHL games, scoring 62 goals and 306 assists for 368 points while adding 1293 penalty minutes. His best offensive season was the 1984–85 season when he set career highs with 14 goals and 53 points. In 1992–93 Hardy and the Kings went to the Stanley Cup Finalsfor the first time in Kings' history. Hardy delivered what was called at the time an "iconic hit" in Game 3, when the Kings were down 3-0 in the second, putting Montreal Canadiens' Mike Keane through the boards with enough force to disrupt two panes of glass to change the momentum of the game. The Kings scored three second-period goals, but lost 4-3 in overtime.
Coaching career
Retiring from the NHL as a King following the 1993–94 season, Hardy turned to coaching in 1999, serving as an assistant coach for the Los Angeles Kings and the Chicago Blackhawks until 2010. He returned to the Kings organization in 2011 as an assistant coach with the club's minor league team, the Ontario Reign of the ECHL. Hardy resigned from the Kings organization in June 2010 after being charged with fourth-degree sexual abuse. Hardy had been arrested in May 2010 after a family member had filed a complaint alleging Hardy had make inappropriate sexual contact with her after they returned to their hotel from a bar. The prosecution eventually decided not to go forward and the charge was dropped. Hardy accepted a position as assistant coach with the Chicago Wolves of the American Hockey League, the minor league team for the St. Louis Blues in August 2014. In June 2016, he was hired as an assistant coach of the Tucson Roadrunners.
As an invited guest hockey analyst for TV appearances and radio broadcasts during the 2014 Stanley Cup Playoffs, Hardy reunited with his former Kings coach Barry Melrose on NHL Network; as a regular analyst during the Western Conference and Stanley Cup Finals on NBC Sports LA with Fred Roggin; and appeared on TSN and the Petros & Money Show on Fox Sports Radio.