An undrafted player, he signed with the Mighty Ducks of Anaheim as a free agent in 2004 and made his NHL debut with the team in 2007.

Glencross was an effective goalscorer and active within the community during his time in Calgary, which led to the team naming him its recipient of the Ralph T. Scurfield Humanitarian Award in 2012.

After splitting the 2014–15 season between Calgary and Washington, Glencross was unable to reach a contract deal with any NHL team and opted to retire as a player.

He went undrafted by an NHL team, but received interest from National Collegiate Athletic Association (NCAA) schools and was considering returning to Brooks for a third season of junior.

[5] He was named the Western Collegiate Hockey Association offensive player of the week for December 15, 2003, after scoring a hat trick against the Colorado College Tigers in a 5–2 win.

[8] Glencross chose to forgo his final two years of college eligibility, signing a professional contract with the Mighty Ducks of Anaheim on March 25, 2004.

[5] He was assigned to the team's American Hockey League (AHL) affiliate, the Cincinnati Mighty Ducks, to complete the 2003–04 season.

But after the Oilers made little effort to negotiate with him, he chose to sign a three-year, $3.6 million deal with Edmonton's provincial rival, the Calgary Flames.

[8] He missed six games in December 2008 with a knee injury,[9] and three more early in the 2009–10 season after he was suspended for a blind-side hit on Chris Drury of the New York Rangers.

[16] His season was ended on March 17 after suffering a leg injury when he was struck by Matt Hendricks of the Colorado Avalanche in a knee-on-knee collision.

[21] His season was ended prematurely by a knee injury after Anaheim's Ben Lovejoy stuck his leg out to cause a knee-on-knee collision.

Despite his reduced offensive output relative to previous seasons, Glencross expected to sign with a new team as a free agent.

[31] He opted against playing in Europe in favour of remaining in Canada with his young family and, on October 20, 2015, announced his retirement as a player.

[32] While Glencross grew up around the rodeo circuit, he did not enter into the sport until he met World Professional Chuckwagon Association driver Rae Croteau Jr. in 2005.

[32] An active member of the community during his playing career, Glencross served as a spokesman for the Special Olympics program,[35] and hosted an annual charity golf tournament in support of Calgary Crime Stoppers.