Smith, more than just about anyone, earned the right to revel in this long-awaited moment.
"It's sweet to clinch it, especially at home in front of the fans," he said.
Team owner Jed York, surrounded by perhaps a dozen reporters in a lively but not raucous 49ers locker room, struck a pragmatic note.
"There is still a long way for us to go," York said, having learned the hard way after famously guaranteeing a playoff appearance following an 0-5 start to last season.
Coach Jim Harbaugh, hired 11 months ago this week, landed somewhere in the middle. He wore a 49ers cap, not a championship one, but he also supported whatever celebrations his players felt appropriate.
"What were our plans if we won the division?" Harbaugh said. "We lean more toward spontaneous celebration. They're happy about it. They realize that there's more out there for us. They're already in there talking about that."
Harbaugh realized this was not the time to focus on continuing red zone troubles, weak third-down performance or 256 yards in penalties over the past three games. His defense dominated despite losing Patrick Willis to a hamstring injury. His team improved to 10-2. His quarterback finished the game with a career-high 142.3 NFL passer rating.
The 49ers are a playoff team again, for the first time since the 2002 season. That was what Sunday was about for the 49ers, and especially for Smith, Frank Gore, Vernon Davis, Willis and all the other long-time sufferers.
"They've gone through each year that they've been here thinking that was going to be the year, and then they fight like heck every single week and there is always disappointment when you don't make that," Harbaugh said. "But these guys, and there is a core group of them, it feels good for them."
This historic 49ers season has been all about how a new coaching staff led by Harbaugh has transformed the product on the field. Yet, Harbaugh also recognized this day wasn't about him.
"For us first-year guys on the team," Harbaugh said, "to be a part of this and do that for them, this step, this game, today, for all those strong-minded men that have been carrying the flag ..."
There really was a flag, too. Gore commandeered a giant one, complete with its own pole and sporting the team logo, from the field into the locker room after the game.
All the while, Harbaugh redirected praise onto his players, consistent with his approach all season. He even largely escaped their attempted Gatorade dousing. Harbaugh's ever-present black sweatshirt came through the ordeal no wetter for wear.
"The guy is so competitive, he juked the Gatorade dump," Smith said. "It barely touched him. That sweatshirt is like a chamois -- the water just rolled off. He is a guy who always shuns the praise."
For the 49ers, Week 13 began with the team securing $850 million in funding for a new stadium in Santa Clara. It ended with Smith completing 74 percent of his passes for 274 yards and two scores while the 49ers' defense, already the NFL's best in points allowed, held the Rams to 157 yards, their lowest total since 2009.
"It's so amazing and ridiculous," nose tackle Isaac Sopoaga said of the 49ers' new place in the world. "I can't even explain this joy and spirit I have."
There was also plenty of one-game-at-a-time talk, from Sopoaga and nearly all the others.
Complacency shouldn't be a problem. Harbaugh said he spent the past week worrying about the Rams sufficiently for Gore to approach him and offer assurances.
"Don't worry," Harbaugh said Gore told him, "we've got this one."
The Rams in their current form pose a bigger threat to coach Steve Spagnuolo's job than they pose to opposing defenses. This season has left them with no coherent direction on offense and fundamental questions about their leadership. Harbaugh now owns as many victories in 12 games as the Rams have managed in their past 54, including 44 under Spagnuolo. But the Rams are a conversation for another day. The 49ers were the relevant story Sunday.
"Hats off to them for continuing to improve and having a great year," Rams defensive end Chris Long said. "They deserve it."
Harbaugh wanted to see how his team would rebound from a 16-6 defeat at Baltimore 10 days earlier. The final score against St. Louis suggests the 49ers responded just fine, and they ultimately did, but the first half was a struggle.
The 49ers led only 9-0 at halftime. They had plateaued in recent weeks, I thought at the time.
A wide-open Davis had dropped a deep pass in the end zone. Davis had also fumbled. Michael Crabtree, who would later break open the game with a 52-yard scoring reception, had dropped a third-down ball. A false-start penalty against Adam Snyder had foiled an attempt to go for it on fourth down. The 49ers' final drive of the half had featured penalties for delay and holding, followed by a 14-yard sack on third-and-17.
The 49ers had picked up where they left off in Baltimore, only against an opponent ill-equipped to do anything about it.
Four days before losing to the Ravens, the 49ers had been sloppier than usual on offense and even special teams during a 23-7 victory over Arizona. They won that game against the Cardinals because Arizona quarterback John Skelton, like the Rams' A.J. Feeley on Sunday, was no match for the 49ers' defense. The Cardinals possessed the ball for only 15:44, their lowest total since at least 1981.
Those viewing each 49ers performance in the context of playoff worthiness could see the imperfections and reasonably wonder what it would mean come January. That thinking, though natural, might hold the 49ers to an unreasonable standard this early in the season. The 49ers don't have to win a championship this week or next. When the playoffs finally do arrive, they'll be playing at home.
This season is already a success no matter what happens next. But as Harbaugh indicated, the 49ers have considered the possibilities. Gore said he took special note a few years ago when another long-suffering organization reached the Super Bowl.
"I just hope that, like that Arizona team [in 2008], we just click at the right time, close to the playoffs, and make that run," Gore said.