Hill finished with 124 yards and two touchdowns in his breakout performance, and the ninth-ranked Tigers handed No. 3 South Carolina its first loss of the season, 23-21 on Saturday night.
"Jeremy Hill's a pretty talented back and has really great speed for a big man," LSU coach Les Miles said. "He certainly came along at the right time."
LSU (6-1, 2-1 Southeastern Conference) substantially outgained South Carolina (6-1, 4-1) 406 yards to 211, but struggled to find the end zone. Three times, LSU settled for field goals after driving at least as far as the Gamecocks 5-yard line, and another drive to the South Carolina 15 stalled on a missed field goal.
But Hill's long score with 5:03 left gave LSU a nine-point lead that proved to be just enough cushion for the Tigers.
The run caused bedlam in Death Valley, exactly what South Carolina coach Steve Spurrier did not want to see — or hear — after jokingly pretending to be momentarily confused this past week about the fact there are two Death Valley's, one at LSU and one at Clemson.
"That was Death Valley," Miles said triumphantly afterward. "That was the place where opponents' dreams come to die — and it was spectacular."
Connor Shaw drove South Carolina for a late TD on a short pass to Bruce Ellington with 1:41 left, and the Gamecocks got the ball once more with 35 seconds left, but LSU's defense held up.
Zach Mettenberger had the latest in a string of inconsistent performances but made enough big throws to sustain scoring drives, finishing 21 of 25 for 148 yards. He had one costly interception returned 70 yards by Jimmy Legree, setting up South Carolina's first TD.
Shaw finished 19 of 34 for 177 yards and two TDs, but was intercepted twice, once by Eric Reid to set up LSU's go-ahead field goal in the fourth quarter, and then on the final desperate play by Craig Loston.
Shaw also was sacked four times — twice by defensive end Sam Montgomery. LSU limited South Carolina, led by star defensive end Jadeveon Clowney, to only sack by linebacker Shaq Wilson.
LSU tamed the Gamecocks' pass rush by pounding the ball on the ground, finishing with a whopping 258-34 advantage in yards rushing.
"Tonight I realized why LSU was preseason No. 1. They can run the ball and stop the run," South Carolina coach Steve Spurrier said. "That was the biggest difference in the game, probably."
LSU's second field goal cut South Carolina's lead to 14-13 early in the fourth quarter, then LSU was right back in scoring range when Shaw overthrew an open receiver and the ball landed in Reid's lap.
Reid returned it to the Gamecocks 22, then LSU drove to the 5 before settling for its third field goal to take a 16-14 lead.
Marcus Lattimore had a quiet night by his standards, gaining only 35 yards on 13 carries, but give the Gamecocks a 14-10 lead in the third quarter when he impressively broke Reid's tackle on a 2-yard scoring run.
Under heavy criticism after failing to produce at touchdown in a loss a week earlier at Florida, LSU's offense was down to only two opening day starters on the line because right guard Josh Williford was unable to return from a concussion and right tackle Alex Hurst was excused for personal reasons.
The unit opened impressively by driving 69 yards on 16 plays, but settled for a field goal after freshman right tackle Vadal Alexander, elevated to starter two weeks earlier, was flagged for a false start on fourth-and-goal from the 1.
The Tigers were moving on their second series as well until Mettenberger's only major mistake — Legree's interception, which was returned to the LSU 1. That set up Ace Sanders' short TD catch to give South Carolina a 7-3 lead early in the second quarter.
After both teams' first four possessions, LSU had a 179-34 advantage in offensive yards, and a 10-2 advantage in first downs, but trailed 7-3.
The Gamecocks were threatening to build on their lead late in the second quarter, but Josh Downs' sack for a loss of 9 yards to the LSU 37 forced a punt.
That allowed LSU to go back in front on Hill's 7-yard touchdown on the first series of the second half.