For all the good things Smith did in his nine years in Chicago, his undoing was his inability to take care of the side of the ball in which he had no background.
The Bears fired Smith on Monday after a 10-6 season. They started 7-1 but fell apart down the stretch, mostly because they couldn't score.
Some Bears players took the news hard. Devin Hester, who blamed media and fans for Smith's firing, was visibly crushed as he cleaned out his locker at Halas Hall following a brief team meeting in which Smith addressed his players.
"We already knew what the news was," Hester said. "Just hearing it from him. The media, the false fans, you all got what you all wanted. Majority of you all wanted him out. As players, we wanted him in. I guess the false fans outruled us. I thought he was a great coach, probably one of the best coaches I have ever been around. He brought me in."
Jay Cutler was more pragmatic, saying that “change isn’t always a bad thing.”
“I think Phil (Emery) and George (McCaskey) and everyone involved, they’re going to do whatever’s necessary, offensively, defensively, special teams wise to put a good product out there next year and make this team the best they can,” Cutler said.
Since Smith took over in 2004, the Bears have ranked higher than 23rd in offense only once. They have ranked 28th or lower four times.
Smith tried four offensive coordinators during his Bears career. His first thought was to run a similar offense to the one he was familiar with when he was defensive coordinator of the Rams, so he hired Terry Shea.
Smith then turned to Ron Turner for his second stint as Bears offensive coordinator. Turner lasted five years in what was the heyday for Smith's offense.
It was during this period that Smith's stubborn allegiance to Grossman became an issue. "Rex is our quarterback," he said over and over again.
Those days Smith often talked frequently about how the Bears "get off the bus running," and the team achieved its offensive identity by pounding the ball with Thomas Jones, then Cedric Benson and finally Matt Forte.
But after the Bears traded for Jay Cutler in 2009 and they still finished 23rd in offense and missed the playoffs, Turner was made the scapegoat and fired.
An extensive job search that included interest in Jeremy Bates, Rob Chudzinski and Tom Clements led the Bears back to Smith's old friend Mike Martz, for whom he had worked in St. Louis. Going from the conservative Turner to the aggressive Martz was quite a philosophical shift for Smith.
Martz's offense sputtered in 2010 but started to come on the next season. Then Cutler broke his thumb in the 10th game, and the team unraveled. The Bears lost five straight, and Martz was fired along with general manager Jerry Angelo, the man who brought Smith to Chicago.
Smith's next move was to go conservative again, this time by promoting offensive line coach Mike Tice. A first-time play caller, Tice made great use of new acquisition Brandon Marshall but struggled to find other reliable targets or to overcome protection issues.
The Bears finished 28th in offense.
The only time Smith enjoyed a fairly efficient offense was in 2006, when the offense ranked 15th in a season that ended in the Super Bowl.
Defensively, the Bears were on the other end of the spectrum under Smith. With perennial Pro Bowlers Brian Urlacher and Lance Briggs as the constants, Smith's defenses usually were among the best in the NFL.
Since 2004, the Bears defense ranks first in the league in takeaways, three-and-out drives forced and third-down percentage and is fourth in scoring defense.
Smith's defenders scored 34 touchdowns, which became a signature of the Bears' style of play.
It was Smith's defense that drove the Bears to their first Super Bowl appearance in 21 years after the 2006 season. Smith and Tony Dungy became the first two African-Americans to coach a Super Bowl team as the Bears took on the Colts.
In Super Bowl XLI, Devin Hester scored on a 92-yard return of the opening kickoff, and safety Chris Harris intercepted Peyton Manning on the Colts' opening drive. But after that it was all Colts, with the enduring memory of the game being Kelvin Hayden's interception of Grossman and 56-yard return for a touchdown.
After the Super Bowl, the Bears appeared set up to be strong contenders for a while. But they failed to reach the playoffs the next three seasons and have made only one postseason appearance in the six seasons since.
During the 2006 season, Smith was the NFL's lowest-paid coach with a salary of $1.35 million. With his success came more power, and he used that to get a new four-year contract worth $5.5 million per season.
He also replaced popular defensive coordinator Ron Rivera with linebackers coach Bob Babich, a controversial move.
"You should trust me as the head football coach to put us in the best position to win games," he said at the time.
Babich lasted two years as coordinator before Smith took over the coordinating duties for a year. In 2010, after being rebuffed by Perry Fewell, Smith promoted defensive line coach Rod Marinelli, who was his first choice for the job when he took over in 2004.
On the day he was hired, Smith said: "The No. 1 goal is to beat Green Bay. One of the first things (then-Chairman) Michael McCaskey said to me, he gave me the history behind the Green Bay-Chicago rivalry and the number of times he wanted us to beat them. I understand that. I feel the pain."
Smith repeated his No. 1 goal many times during his tenure, but he was not able to achieve it often enough. After winning seven of his first 10 games against the Packers, Smith lost eight of his next nine, including the NFC championship game in January 2011 at Soldier Field. The Packers went on to win the Super Bowl.
Smith's teams won the NFC North three times in nine years, but over the same period the Packers won the division six times. Smith was named NFL coach of the year in 2005, when he led the Bears to an NFC North title in his second year.
Smith, who is still owed a reported $5 million for next year, won 81 games in his Bears career, placing him third in franchise history behind George Halas and Mike Ditka. He finished his tenure 18 games above .500.
As for Smith's future, his agent Matthew Smith of IMG said: "He's ready to coach. He's ready to be a head coach in the NFL somewhere in 2013.''