Smith capped a club playoff-record 209-yard rushing performance with a 17-yard touchdown 11:26 into overtime to lift the Miami Dolphins to a 23-17 victory over the Colts in an AFC wild card game.
The 209 yards is the second-best in NFL playoff history, behind only Eric Dickerson's 248 yards in a 1985 postseason game for the Los Angeles Rams against Dallas. Larry Csonka held the team record with 145 yards against Minnesota in Super Bowl VIII in January 1974.
With 40 carries, Smith set a playoff record, surpassing the mark of 38 shared by John Riggins and Ricky Bell.
"I didn't have any idea the game was going to end up like it did today with me playing such a large role," Smith said.
The Dolphins (12-5) will meet the Oakland Raiders (12-4) on January 6 in the divisional playoffs.
Indianapolis (10-7) had a chance to win, but Mike Vanderjagt missed a 49-yard field goal attempt in overtime. He missed just two field goals the entire season (25-of-27) and converted three, including a 50-yarder, in regulation.
"I let my teammates down, I let the organization down and I let the city of Indianapolis down," Vanderjagt said. "It's a pretty big burden to carry into the offseason, but nothing can change that now."
Colts coach Jim Mora slipped to 0-6 in postseason games, four with New Orleans and two with Indianapolis.
"I don't feel snakebit at all," Mora said. "We just have to get better so we can get the job done. We'll be back."
For the first time in seven seasons, an NFL playoff game was blacked out in the local television market after Miami fans failed to sell out Pro Player Stadium. Since the Dolphins fell 7,500 tickets short at Friday's deadline, the league enforced its rule of banning local telecasts.
Those fans ended up missing an epic performance by Smith, who had 87 yards on 16 carries in the first half and 112 yards on 24 attempts in the second half and overtime.
On his final carry, Smith stutter-stepped to his right, deftly followed his blockers and carried cornerback Jeff Burris into the end zone from inside the 5 for his second TD to give Miami the come-from-behind win.
"I kind of sat down and played possum," Smith said of the winning touchdown. "I acted like I was going inside, then I bounced outside and there was nothing but green grass in front of me."
A journeyman for six NFL seasons, Smith beat out J.J. Johnson in training camp for the role of feature back and produced 1,139 yards -- the second-best total in club history -- and 14 touchdowns.
Smith's previous career high was 157 yards, and he reached the century mark four times this season. But he made his biggest splash today when it mattered most for the Dolphins.
"Nothing he does surprises me anymore," Fiedler said. "He broke tackles on everyone today and just did an incredible job."
"Breaking tackles is certainly his strength," Colts safety Chad Cota said of Smith. "He gets hit once and he just keeps going. We knew their passing game was struggling and we needed to shut down the run, but it just wasn't happening."
Miami rallied from a 14-0 halftime deficit, overcoming three interceptions by Fiedler, thanks to Smith and a defense that held Indianapolis' high-powered offense to a field goal after halftime.
"We got to this point by playing defense and running the ball, playing physical, and that is what happened today," Dolphins coach Dave Wannstedt said.
MIami opened the second half with an 11-play, 70-yard drive that lasted nearly seven minutes. Smith carried seven times for 42 yards and capped the drive with a two-yard touchdown.
Olindo Mare, who earlier missed a 38-yard field goal, converted a 38-yarder 4:37 into the fourth quarter to pull the Dolphins within 14-10. Smith broke off a 19-yard run to the Indianapolis 27 to set up the kick.
Indianapolis responded with a nine-play, 45-yard drive that resulted in a 50-yard field goal by Vanderjagt, increasing the lead to 17-10 with 4:55 left.
But it proved more than enough time for the Dolphins, who went 80 yards in 14 plays. Fiedler and Smith had three-yard runs on 3rd-and-1 plays to keep the drive alive. Fiedler also hit O.J. McDuffie with passes of 19 and 13 yards before the TD toss to Weaver.
Miami won the coin toss but failed to score on its first overtime possession.
Indianapolis appeared ready to take advantage of its opportunity when Peyton Manning hit Marvin Harrison with a 30-yard pass. The Colts drove to the Miami 32 when the drive stalled but rested its fortunes on the reliable foot of Vanderjagt.
Mora even nixed an offsides penalty against Miami on a completion to Harrison to the Miami 32. The penalty would have given the Colts a 3rd-and-7 at the Miami 37. Instead, Mora took the completion, which left Indianapolis with a 4th-and-2 at the 32.
"Yes, I considered it," Mora said of taking the penalty. "It would have been 3rd-and-7. I looked at Mike and he said 'I can make it.' He said I wouldn't second-guess my decision to kick the field goal, not with Mike's ability to come through in the clutch."
But Vanderjagt was wide right 5:44 into overtime.
"I caught some turf before I hit the ball and that's what made it go right," Vanderjagt said. "I was born to be in that situation."
Vanderjagt held his head in his hands as the Dolphins drove 61 yards in 11 plays. Fiedler hit Jeff Ogden with a six-yard pass on 3rd-and-3 to the Indianapolis 48 to keep alive the drive. Fiedler also ran for two yards on 3rd-and-1 and hit Oronde Gadsden with a 13-yard pass to the Indianapolis 23. Two plays later, Smith scored the winning touchdown.
"It's crazy how we have a chance to win after they miss a field goal and we caught a break and won," Dolphins linebacker Zach Thomas said.
Fiedler was just 5-of-14 for 42 yards with three interceptions in the first half. He was 14-of-20 for 143 yards in the second half and rushed for 43 yards on seven carries.
"He didn't lose his composure," Wannstedt said of Fiedler. "When we came in at halftime we talked about what we could do in the second half to not put him in situations as far as throwing the ball."
Miami played two previous overtime playoff contests, beating Kansas City, 27-24 on Christmas Day 1971 and losing to San Diego, 41-38, in January 1982.
It was the fourth overtime playoff game for the Colts, but the first since the franchise moved to Indianapolis.
NFL rushing champion Edgerrin James carried 21 times for 107 yards and caught three passes for 33 yards but was overshadowed by Smith.
"There's a lot of things you can say, this or that, but the bottom line is we lost," James said. "We win with Mike and we lose with Mike. There's no way we're going to put everything on Mike's shoulders."
Manning completed 17-of-32 passes for 194 yards, including a 17-yard touchdown to Jerome Pathon.
Vanderjagt kicked a 32-yard field goal with 7:49 left in the first quarter to give Indianapolis a 3-0 lead.
Fiedler committed a turnover on each of Miami's next three possessions. On the first, Cota picked off a pass in the end zone intended for Tony Martin. On the following play, James broke off a 34-yard run, but the drive stalled and Indianapolis punted.
Fiedler created a golden opportunity for the Colts when he threw the ball at defensive end Chad Bratzke on a flanker screen. Bratzke deflected it up in the air and picked it off at the Miami 25.
But with 2nd-and-goal at the 8, Manning threw two straight incompletions and the Colts had to settle for a 26-yard field goal by Vanderjagt.
"We had chances in the first half," Manning said. "The defense got us good field position with the turnovers and we got field goals and didn't get touchdowns."
But Indianapolis did get a touchdown after Fiedler's third turnover, a 23-yard interception return by Cota to the Miami 18.
Two plays later, Manning hit Pathon in the corner of the end zone for a 17-yard touchdown and connected with tight end Ken Dilger on the two-point conversion, giving Indianapolis a 14-0 lead with 7:47 left in the half.