Whisenhunt coached six years for the Cardinals, compiling a 45-51 record, including two NFC West division titles and the franchise's one and only trip to the Super Bowl.
Several of Whisenhunt's assistants have also been let go by the team. Russ Grimm (Assistant Head Coach/Offensive Line), Mike Miller (Offensive Coordinator), Chad Grimm (Offensive Quality Control), John McNulty (Quarterbacks), Frank Reich (Wide Receivers) and Tommie Robinson (Running Backs).
Tight ends coach Freddie Kitchens and special teams coach Kevin Spencer were not affected by the firings.
No changes have been made with the defensive assistants to this point.
Under Whisenhunt, the Cardinals struggled following the retirement of quarterback Kurt Warner after the 2009 season. In the three seasons that followed consecutive playoff berths, the Cardinals went 18-30 while starting six different quarterbacks.
In 2012, the Cardinals suffered their worst loss in franchise history, a 58-0 drubbing at the hands of the Seattle Seahawks in Week 14.
The Cardinals have also suffered losing streaks in each of the last three seasons of at least six games, including a nine-game skid this season.
Whisenhunt had one year remaining on his contract.
The search for a new coach (and general manager) begins with the new year, and Cardinals defensive coordinator Ray Horton, a hot coaching commodity around the league, would seem to have the early inside track on landing the head coaching post with the Cardinals.
Horton's defense ranked 12th in the league in yards allowed and 17th in points allowed this season.
Whisenhunt was one of seven NFL head coaches relieved of their duties Monday. The others were Philadelphia's Andy Reid, Buffalo's Chan Gailey, Cleveland's Pat Shurmur, San Diego's Norv Turner, Chicago's Lovie Smith and Kansas City's Romeo Crennel.