The 2011San Francisco 49ers season was the franchise's 66th season overall, and 62nd in the National Football League (NFL). It is the first season under head coachJim Harbaugh and general manager Trent Baalke. The 49ers rebounded from their disappointing 2010 season to end their streak of eight consecutive non-winning seasons. After defeating the St. Louis Rams in week 13 and attaining a 10–2 record, the team clinched the NFC West and made their first playoff appearance since 2002 (under head coach Steve Mariucci). The 49ers ended the regular season with a 13–3 record, their best since 1997 and earned a bye in the first round of the playoffs. In the Divisional Playoffs they defeated the New Orleans Saints 36–32 and were in the NFC Championship for the first time since 1997 where they lost against the New York Giants 20–17 in overtime, coming just short of returning to the Super Bowl for the first time since 1994. Despite their most successful season in years, the 49ers were 31st in the league in third down conversion percentage in the regular season (29.1) and were 17.9 percent in the playoffs.
Owner Jed York announced that he would hire a general manager and the new GM would make a decision on the new head coach to replace Mike Singletary after the 49ers loss to the St. Louis Rams on December 26, 2010 that eliminated the team from the postseason. On January 5, the 49ers promoted the vice president of player personnel, Trent Baalke, to the position of general manager. On January 7, the 49ers hired Stanford head coach Jim Harbaugh to be the 18th head coach of the San Francisco 49ers.
With the hiring of a new head coach, many of the assistant coaches were replaced. Out of the coordinators and position coaches from last season, only running backs coach Tom Rathman, defensive line coach Jim Tomsula, and offensive line coach Mike Solari were retained. The coaching staff features Greg Roman as the new offensive coordinator and Vic Fangio as the new defensive coordinator, both previously assistant coaches under Harbaugh at Stanford. Former Cleveland Browns assistant head coach and special teams coordinator Brad Seely was hired for the same roles with the 49ers. Geep Chryst is the new quarterbacks coach, Reggie Davis is the new tight ends coach. John Morton is the new wide receivers coach, and Tim Drevno is a new offensive line coach to help out Mike Solari. Jim Leavitt is the new linebackers coach and Ed Donatell is the new secondary coach. The staff also features defensive assistants Peter Hansen and Ehiro Evero, offensive assistant Bobby Engram, and special assistant to the head coach Bill Nayes.
^[a] The 49ers acquired this fourth-round selection from the San Diego Chargers along with a 2010 third-round selection (#91 overall; used to select LBNavorro Bowman) and a 2010 sixth-round selection (#173 overall; used to select RBAnthony Dixon) in exchange for a 2010 third-round selection (#79 overall).
^[e] The 49ers acquired this second-round selection from the Denver Broncos in exchange for their second-round selection (#45 overall), a fourth-round selection (#108 overall), and a fifth-round selection (#141 overall).
^[f] The 49ers acquired this third-round selection (#80 overall) and this sixth-round selection (#180 overall) from the Jacksonville Jaguars in exchange for their third-round selection (#76 overall).
^[g] The 49ers acquired this fifth-round selection (#163 overall) from the Green Bay Packers in exchange for their sixth-round selection (#174 overall) and a seventh-round selection (#231 overall).
On the night of Saturday, August 20, 2011, according to a copyrighted online article appearing in the headlines of the Sunday, August 21, 2011 online edition of the AOLHuffington Post Sports News page: "A man wearing a shirt slamming the San Francisco 49ers was seriously wounded as gunfire erupted in the parking lot after the team's NFL preseason game, while another man sustained lesser injuries in an earlier shooting, police said. The violence occurred after the 49ers' 17–3 victory Saturday night over the Oakland Raiders at Candlestick Park, police Sgt. Michael Andraychak said. A 24-year-old man was treated at San Francisco General Hospital for life-threatening injuries, and a 20-year-old man was hospitalized with less serious wounds, Andraychack told the Associated Press. Their names were not released. The violence comes months after a San Francisco Giants' fan was severely beaten by two men in Los Angeles Dodgers' gear outside Dodger Stadium, after the teams' season opener March 31. Two suspects have been charged in the case."
The NFL has officially canceled all future preseason games between the two teams.
San Francisco trailed early in the first quarter as Ravens kicker Billy Cundiff got a 39-yard field goal, yet the 49ers answered with a 45-yard field goal from kicker David Akers. Baltimore struck back in the second quarter with Cundiff making a 23-yard field goal.
San Francisco began the third quarter with a 52-yard field goal from Akers, but the Ravens opened the fourth quarter with quarterback Joe Flacco completing an 8-yard touchdown pass to tight end Dennis Pitta, followed by Cundiff nailing a 39-yard field goal. The Niners tried to rally, but Baltimore's defense held on to preserve the win.
Vernon Davis 1-yard pass from Alex Smith (David Akers kick), 49ers 13–3
Frank Gore 5-yard run (David Akers kick), 49ers 20–3
PIT – Ben Roethlisberger – 25/44, 330 yards, 3 interceptions
SF – Alex Smith – 18/31, 187 yards, 1 touchdown
PIT – Rashard Mendenhall – 15 carries, 64 yards
SF – Frank Gore – 18 carries, 65 yards, 1 touchdown
PIT – Jerricho Cotchery – 5 carries, 93 yards
SF – Vernon Davis – 6 catches, 72 yards, 1 touchdown
PIT – Troy Polamalu – 7 tackles
SF – NaVarro Bowman – 7 tackles, 1 assist
The 49ers traveled home for a game on Monday Night Football against the Steelers. It was delayed due to a power outage in their stadium. The lights went off again in the 2nd quarter when the 49ers were leading 6 to 0 which eventually became the score at halftime. In the 2nd half the 49ers would go on a 14 to 3 run to make the final score 20 to 3 and improve their record to 11–3.
Alex Smith's 14-yard touchdown pass to tight end Vernon Davis with 9 seconds left gave San Francisco their first playoff win since 2002 at the end of a wild, back and forth final quarter which featured four lead changes in a span of 3:53. Davis' game winning touchdown catch occurred four days after the 30th anniversary of The Catch – Joe Montana's famous touchdown pass to Dwight Clark – known as one of the most famous plays in San Francisco 49ers history. Sports writers and 49ers fans have taken to referring Davis' catch as The Catch III. This game was voted the number 1 game of 2011 by NFL.com.  With the win, the 49ers improved to 14–3 and faced the New York Giants at Candlestick Park in the NFC Championship Game.
In a defensive game, the New York Giants won in overtime on a 31 yard field goal by Lawrence Tynes. Kyle Williams, a rookie, took over punt return duties for an injured Ted Ginn, Jr. and had what many 49ers fans consider the worst playoff performance in team history. Williams fumbled three times, losing two of them, that led to 10 Giants points, including setting up the game winning field goal. He also dove for a punt, instead of just letting it go. The 49ers' offense also struggled to move the ball at times throughout the game. They did not convert a 3rd down conversion for the first three quarters. With the loss, the 49ers season ends with a 14-4 record.