Montgomery joined 96.7 FM's The Ticket on Dec. 5, during which he was asked questions about Tyler Seguin's private life and whether he smoked marijuana during his time as head coach of the University of Denver.
The 50-year-old was fired in the midst of his second season with Dallas due to what was described as "unprofessional conduct." Stars general manager Jim Nill said he was made aware of a "material act of unprofessionalism" over the weekend, but added that the incident didn't involve past or present players or a criminal investigation, and it didn't relate to the league's new zero-tolerance policy toward inappropriate or abusive behavior.
The Stars qualified for the playoffs and advanced to Game 7 of the second round last season in Montgomery's first year at the helm. Dallas lost eight of its first nine games this campaign but experienced a drastic turnaround and is now 18-11-3 and holds the first wild-card position in the Western Conference with 39 points.
After learning of Montgomery's firing, Seguin said "no one expected this."
Longtime assistant Rick Bowness is serving as interim head coach and won his first game as bench boss Tuesday night.