Hartley was an ice hockey analyst for the French-language RDS television channel until 2011, when he became the head coach of the ZSC Lions of the Swiss National League A.
After guiding the team to a championship, his accolades caught the eye of the Laval Titan of the Quebec Major Junior Hockey League (QMJHL).
Hartley's success with the Bears caught the eye of then-Avalanche general manager Pierre Lacroix, who was looking for a replacement for Marc Crawford, who had suddenly resigned after a surprising first round playoff exit.
Motivated by Ray Bourque's desire to win a Stanley Cup championship, the Avalanche coasted through the league with a 52–16–10–4 record, a seventh consecutive division title along with the Presidents' Trophy.
The playoffs began with a first round sweep of the eighth seed Vancouver Canucks before enduring a seven-game scare by the Los Angeles Kings in the Western Semi-Finals before taking down the St. Louis Blues in five games, setting up a Stanley Cup Finals matchup with the Eastern Conference's top seed, the New Jersey Devils.
Another notable milestone from the 2000–01 NHL season for Hartley included coaching the North American All-Star team to a 14–11 victory on home ice.
At the start of the playoffs, Hartley became the first head coach since Billy Reay to guide his teams to four consecutive conference final appearances.
After two grueling playoff series victories over the Los Angeles Kings and San Jose Sharks, in a repeat of the 1997 Western Finals, the team bowed to the archrival Detroit Red Wings, who would go on to win the Stanley Cup.
Hartley's tenure with the Avalanche ended on December 17, 2002, when the team endured a 10–8–9–4 start and he was replaced by assistant coach Tony Granato.
After original goaltenders Kari Lehtonen and Mike Dunham were injured, Hartley was forced to use prospects Adam Berkhoel and Michael Garnett along with journeyman Steve Shields, the Thrashers posted the first winning season in franchise history with a 41–33–8 record, but fell short for a playoff appearance after losing out to the Tampa Bay Lightning in the final week of the regular season by two points.
[8] On April 17, 2012, Hartley led ZSC Lions to a Game 7 upset victory against favourite SC Bern to claim the Swiss championship.
[9] On December 20, 2016, the Latvian Ice Hockey Federation announced that Hartley agreed to become the head coach of Latvia national team.
This historical victory marked the first time Latvia won against the superior Canadian men's national ice hockey team.