It was the team's first playoff appearance in St. Louis, their first since 1989, and their first division title since 1985.
The Rams were undefeated at home for the first time since 1973. On the road, the Rams were 5–3. In the post-season, they defeated the Minnesota Vikings by a score of 49–37 in the NFC Divisional Playoffs and went on to defeat the Tampa Bay Buccaneers 11–6 in the NFC Championship Game. Both of those games were played in St. Louis. The Rams then won their first ever Super Bowl title, defeating the Tennessee Titans by a score of 23–16 in Super Bowl XXXIV. The game was played on January 30, 2000 at the Georgia Dome in Atlanta. It was also the franchise's first NFL World Championship since 1951, when the Rams played in Los Angeles. The Rams also became the first "dome-field" (indoor home games) team to win a Super Bowl.
It was the first season of the Rams' "Greatest Show on Turf" offense. The 1999 Rams remain one of only four teams in NFL history to score more than 30 points twelve separate times in a single season. On defense, the Rams recorded seven interceptions returned for touchdowns, third most in NFL history.
Kurt Warner at the Super Bowl XXXIV post-game press conference
Warner was the backup quarterback for the St. Louis Rams during the 1998 regular season and the 1999 preseason. When starting quarterback Trent Green was injured in a preseason game, Warner took over as the starter. With the support of running back Marshall Faulk and wide receivers Isaac Bruce, Torry Holt, Az-Zahir Hakim and Ricky Proehl, Warner completed one of the top seasons by a quarterback in NFL history by throwing for 4,353 yards with 41 touchdown passes and a completion rate of 65.1%. The Rams' high-powered offense was nicknamed "The Greatest Show on Turf" and registered the first in a string of three consecutive 500-point seasons, an NFL record. Warner threw three touchdown passes in each of the first three games in the 1999 season, his first three NFL starts. He is the only NFL quarterback in history to accomplish that feat, and only the second other than Dan Marino to do it in his first two NFL starts.
Warner really drew attention, however, in the season's fourth game against the San Francisco 49ers, who had been NFC West Division champs for 12 of the previous 13 seasons. The Rams had lost 17 of their previous 18 meetings with the 49ers and had a 3–0 record along with the 49ers' 3–1 record. Warner proceeded to throw three touchdown passes on the Rams' first three possessions of the game and four in the first half to propel the Rams to a 28–10 halftime lead on the way to a 42–20 victory. Warner finished the game with five touchdown passes, giving him 14 in four games and, more importantly, the Rams a 4–0 record. After many years of defeats and losing records, football experts finally had to take notice.
Warner's breakout season from a career in anonymity was so unexpected that Sports Illustrated featured him on their October 18 cover with the caption "Who IS this guy?"  He was named the 1999 NFL MVP at the season's end.
In the NFL playoffs, Warner led the Rams to a Super Bowl XXXIV victory against the Tennessee Titans. He threw for two touchdowns and a Super Bowl record 414 passing yards, including a 73-yard touchdown to Isaac Bruce when the game was tied with just over two minutes to play. Warner also set a Super Bowl record by attempting 45 passes without a single interception.
As expected, this match between the two high powered offenses produced a lot of points (86), and yards (880, 475 by St. Louis, 405 by Minnesota). But after falling behind 17–14, St. Louis stormed to victory with 35 consecutive second half points to open a 49 to 17 lead early in the fourth quarter. It was also the first NFL Playoff game ever played in St. Louis.
The Rams and Buccaneers would slug it out for most of the game, with the Buccaneers defense holding the Rams highly-potent offense in check. Tampa Bay, weak on offense, would only muster two field goals, and gave up a costly safety in the second quarter when a bad snap from center went over the head of rookie quarterback Shaun King and out of the endzone. Despite this, the Buccaneers nursed an unusual 6–5 lead into the 4th Quarter. The Rams broke open a defense dominated game when Kurt Warner threw a touchdown pass to Ricky Proehl, his first and only touchdown of the season, with 4:44 left in the game. The Buccaneers would mount a drive on their final possession, however a controversial replay overturned what appeared to be a 2nd down reception by Buccaneers wide receiver Bert Emanuel which would have set up a short-yardage 3rd down.
Emanuel dove for a catch and successfully clasped the ball between two hands, then upon falling, the nose of the ball touched the turf while remaining in Emanuel's hands. The ruling on the field was a completed catch, but was overturned on review because the ball had touched the ground before Emanuel was deemed in possession of it. This was consistent with NFL rules for the 1999 season, but in the following offseason the NFL changed this rule such that Emanuel's play would have been ruled a catch under the change. Following this, the Buccaneers threw incomplete passes on 3rd and 4th down and the Rams were able to kneel out the clock.
The first half of Super Bowl XXXIV had been uncharacteristically low-scoring for St. Louis, as they scored only three Jeff Wilkins field goals in the first half. The Rams finally got into the end zone in the third quarter, with a 9-yard touchdown pass from Kurt Warner to Torry Holt, giving St. Louis a 16–0 lead. Tennessee, however, scored 16 unanswered points with two Eddie George touchdown runs (1- and 2-yards respectively, the first with a failed two-point conversion attempt), and a 43-yard Al Del Greco field goal.
On St. Louis's first play from scrimmage after Tennessee's tying field goal, Kurt Warner threw a 73-yard touchdown to Isaac Bruce to take a 23–16 lead with barely two minutes left in the game, which would give Tennessee one more chance to tie the game with a touchdown.
The Tennessee Titans took over the ball at their own 10-yard line with 1:54 left in the game after committing a holding penalty on the ensuing kickoff. McNair started out the drive with a pair of completions to Mason and Wycheck for gains of 9 and 7 yards to reach the 28-yard line. Then after throwing an incompletion, defensive back Dre' Bly's 15-yard facemask penalty while tackling McNair on a 12-yard scramble gave the Titans a first down at the St. Louis 45-yard line. On the next play, St. Louis was penalized 5 yards for being offsides, moving the ball to the 40-yard line with 59 seconds left. McNair then ran for 2 yards, followed by a 7-yard completion to wide receiver Kevin Dyson. Three plays later, with the Titans facing 3rd down and 5 to go, McNair was hit by two Rams' defenders, but he escaped and completed a 16-yard pass to Dyson to gain a first down at the Rams 10-yard line. Tennessee then used up their final timeout with just 6 seconds left in the game, giving them a chance for one last play. McNair threw a short pass to Kevin Dyson down the middle, which looked certain to tie up the game, until Rams linebacker Mike Jones tackled Dyson at the one-yard line as time expired. Dyson tried to stretch his arm and the football across the goal line, but he had already gone down, so it was too late. This final play has gone down in NFL history as simply "The Tackle".