Klemn played his junior hockey with both Seattle and Spokane of the WHL as a forward. In his second season in Spokane and in his second season, he scored 65 points as a forward to lead his team to the WHL Championship and the Memorial Cup Championship.
Klemm, who was often paired with the offensively adventurous Sandis Ozolinsh, was part of a very successful team in Colorado, as they won the Campbell Conference Bowl three times and the Stanley Cup twice. On October 17, 1998 Klemm set a club record when he scored two goals nine seconds apart.
After Colorado won the 2001 Stanley Cup, they signed Patrick Roy, Joe Sakic and Rob Blake to contracts totalling over 100 million dollars and decided not to resign Klemn. Klemn signed with the Blackhawks on the first day of free agency.
After 2 and 1/2 seasons in the Windy City Klemm was moved to Dallas where played close to 3 seasons with the Stars. He ended his NHL career with a brief appearance in Los Angeles in 2007-08.
In 773 NHL regular season games Jon Klemm scored 42 goals and 100 assists for 142 points.
Okay, sure, Wayne Gretzky had more points in a few different seasons than Klemm did in his lengthy career, but very quietly Klemm was a valuable member of the Colorado Avalanche teams that won two Stanley Cups. He was willing to do anything and everything the team asked of him. He didn't add much offensively, and didn't have the mean temperament to make the highlight reels with hard hits. He just quietly did his job, nicely filling minutes on the Colorado blue line or on the 4th forward line.