Rookie Jonas Jerebko had a career-best 22 points and Rodney Stuckey added 21 before fouling out for Detroit, which lost its seventh straight.
Jerebko's 3-pointer halfway through the fourth quarter gave the Pistons an 87-86 lead. The Clippers answered with a 7-0 run, including consecutive baskets from Thornton, to regain the lead for good. Thornton was 5 for 6 from the floor and scored 12 points in the final period.
"I was asleep the first three quarters, but I woke up in the fourth quarter," he said. "Getting a win here makes it a pretty good trip."
The Clippers were outrebounded 43-35 but made up for it by blocking nine Detroit shots and holding the Pistons to 40 percent field-goal shooting while making almost 60 percent. The Clippers outscored the Pistons 46-26 in the paint.
"We've got a lot of guys who can post up," coach Mike Dunleavy said. "We took advantage of it."
Will Bynum scored 14 points and had nine assists and Ben Wallace grabbed 16 rebounds for Detroit, which was missing three of its most able offensive contributors.
"Their interior passing was superior to ours and Kaman did a really good job of sizing up what he wanted to and knocking down open looks," Pistons coach John Kuester said.
The Pistons were without guard Ben Gordon, who left Wednesday's loss to Cleveland with a sprained left ankle. He joined Richard Hamilton (ankle) and Tashaun Prince (back) on the sick list.
Rookie Austin Daye made his first career start in Gordon's place and scored a career-best 13 points.
Eric Gordon, playing his second game since missing eight straight with a groin injury, came off the bench to score 14 points for the Clippers.
"We had a lot of guys chip in," added Dunleavy, who said he was happy to hear his son, Mike, played his first game in almost a year for Indiana on Friday.
Notes: Los Angeles C DeAndre Jordan (right ankle sprain) missed his third straight game. ... Davis was assessed a technical foul after arguing with an official in the first quarter. ... Detroit's last home loss to the Clippers was Feb. 19, 2001.