Tolbert scored twice against his former team and DeAngelo Williams turned a tipped pass from Cam Newton into a 45-yard touchdown reception.
Carolina (5-9) won consecutive games for the first time since last December.
The Chargers (5-9) will miss the playoffs for the third straight season and clinched their first losing season since 2003, when they were an NFL-worst 4-12. Coach Norv Turner is expected to be fired at season's end, most likely along with general manager A.J. Smith.
Tolbert, who left San Diego as a free agent in March, capped Carolina's first two drives with 1-yard scoring runs. His second TD was set up when Philip Rivers lost a fumble. Rivers lost another fumble in the fourth quarter, his 22nd turnover this season and 47th in less than two full seasons.
San Diego lost for the eighth time in 10 games, and dropped its third straight home game.
The only bright spot for the Chargers came when Antonio Gates tied Hall of Famer Lance Alworth's club record with his 81st career touchdown catch, a 9-yarder from Rivers with 14:02 left. Gates just got his second foot down before going out of bounds.
That score was set up when the Chargers got their best starting field position of the day, on the Carolina 38, when Larry English recovered Williams' fumble.
Until then, the Chargers had run only two plays from scrimmage in Panthers territory, reaching the 44.
Gates' TD allowed the Chargers to avoid their first shutout since a 34-0 loss at Kansas City on Oct. 31, 1999, a span of 211 regular-season games.
The Chargers had kept their faint playoff hopes alive with a 34-24 upset win at Pittsburgh a week earlier, but couldn't get out of their own way at home.
Newton was 19 of 33 for 231 yards and two touchdowns as the Panthers followed up their 30-20 upset victory against Atlanta with their first consecutive victories since beating Houston and Tampa Bay last December.
Tolbert doubled his touchdown production this season. His two touchdowns in a span of 3:35 were one more than San Diego running back Ryan Mathews has this season. Mathews left with a shoulder injury early in the second quarter and didn't return.
Tolbert leaped over the top of the pile for his first TD to cap the game's opening drive, which went 80 yards in 13 plays.
Rivers dropped back to pass on the Chargers' first possession and the ball flew out of his hand for a fumble that was recovered by Nate Chandler at the San Diego 21. Four plays later, Tolbert went in standing up to make it 14-0.
After forcing the Chargers to punt, the Panthers needed six plays to go 72 yards and take a 21-0 lead. On second-and-10 from the Chargers 45, Newton's pass was tipped by Jarret Johnson. Williams plucked it out of the air and took it all the way in for a touchdown.
The Panthers piled on with Graham Gano's 33-yard field goal with six seconds before halftime and Newton's 4-yard scoring pass to Steve Smith midway through the third quarter for a 31-0 lead.
Rivers was 16 of 23 for only 121 yards. San Diego was outgained 372 yards to 164.
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Carolina 31, San Diego 7
Carolina 21 3 7 0 31
San Diego 0 0 0 7 7
Car • Tolbert 1 run (Gano kick), 8:29.
Car • Tolbert 1 run (Gano kick), 4:54.
Car • D.Williams 45 pass from Newton (Gano kick), :58.
Car • FG Gano 33, :06.
Car • S.Smith 4 pass from Newton (Gano kick), 8:56.
SD • Gates 9 pass from Rivers (Novak kick), 14:02.
Attendance • 53,832.
First downs 29 12
Total Net Yards 372 164
Rushes-yards 39-155 16-70
Passing 217 94
Punt Returns 2-32 1-23
Kickoff Returns 2-52 2-49
Interceptions Ret. 0-0 0-0
Comp-Att-Int 19-33-0 16-23-0
Sacked-Yards Lost 2-14 6-27
Punts 4-39.5 6-48.5
Fumbles-Lost 2-1 4-2
Penalties-yards 6-48 9-70
Time of Possession 37:32 22:28
Rushing • Carolina, D.Williams 22-93, Tolbert 9-40, S.Smith 1-15, Newton 4-7, A.Smith 3-0. San Diego, Brinkley 6-42, Mathews 4-22, Rivers 3-4, Battle 3-2.
Passing • Carolina, Newton 19-33-0-231. San Diego, Rivers 16-23-0-121.
Receiving • Carolina, S.Smith 6-57, Olsen 5-56, D.Williams 2-51, Tolbert 2-24, Murphy 2-18, Barnidge 1-20, Hartsock 1-5. San Diego, Gates 4-31, Brinkley 3-14, Mathews 3-8, Floyd 2-39, Battle 2-12, Rosario 1-9, Spurlock 1-8.
Missed Field Goals • None.