The Dodgers pounded out 16 hits, which matches the most allowed by the Marlins this season.
"Josh Johnson is a really good pitcher and he pitches through three innings. There's no breaks. It's a tough lineup," Kershaw said of his teammates.
With ample run support, Kershaw settled after yielding a second-inning homer to Giancarlo Stanton, and scattered three hits with eight strikeouts in eight innings.
"JJ was off, with everything," Marlins manager Ozzie Guillen said. "Velocity was down. If we're going to face a team of that caliber, you've got to bring your best stuff. If you're not, you're going to get killed."
The Marlins have dropped four straight games, and on Sunday they will try to avoid being swept in the finale of their 11-game road trip.
"I was terrible," said Johnson, who saw his ERA rocket to 4.00. "That was pretty much it -- everything, command."
For Johnson, it was a rough go, as the right-hander threw 45 of his 89 pitches in the first inning. He's now lost four straight starts for the first time in the same season. There was a stretch over two years where he dropped six straight -- Sept. 7, 2006-July 4, 2007.
"It's part of it," Johnson said of the personal losing streak. "But you don't want to pitch like that. I was terrible. We got one in the first, and I gave that up pretty quick. We got another one, and I gave that up."
Entering the season, Johnson had allowed as many as 10 hits once in his career. Now, it's occurred four times this year, with the last on April 29.
Being hit so hard raised the issue of Johnson's health. The 28-year-old missed most of 2011 with right shoulder inflammation. And he hasn't missed a start this year, as his inning count reached 157 1/3.
But after the game, Johnson insisted he is fine. In fact, he says he felt stronger than he has in a while.
"I felt great physically," the Miami ace said. "Felt probably the best I have in the last four or five starts."
Guillen basically is chalking it up to a bad game.
"We keep asking how he feels, how he's doing, his health," Guillen said. "As manager of any ballclub, I never risk any player who comes and says something is sore. I hope there is nothing wrong with him. I don't think so. Today, he just didn't have a good game."
Miami did receive a boost from Stanton, who blasted a solo shot in the second inning off Kershaw. It was his seventh on the road trip, the most ever by a Marlin. Stanton now has 28 on the season.
"The only one positive and reason to smile is when he comes to the plate," Guillen said. "At least we can enjoy something every two innings."
Another positive is Donovan Solano, who had an infield single in the sixth inning, extending his hit streak to nine games. The rookie actually caught a break, because replays showed he was out by a half a step.
The infield hit was the last by the Marlins on a day the game slipped away early.
The Marlins claimed a first-inning lead when Gorkys Hernandez doubled to open the game, and he scored on Jose Reyes' RBI groundout. Otherwise, it was all Los Angeles.
Andre Ethier had four hits, and he homered off Wade LeBlanc in the fifth inning. Ethier broke a Los Angeles Dodgers record with 10 consecutive hits, passing Ron Cey, who did it July 2-4, 1977.
In the first inning, the Dodgers sent nine to the plate, collected six hits and opened a 4-1 lead. Gonzalez, acquired from the Red Sox earlier in the day, became the sixth Dodger ever to homer in his first at-bat. He blasted a three-run homer. In the second inning, after Stanton's homer made it 4-2, Ellis homered.
The 45-pitch first inning might have been the worst frame of Johnson's career.
"When you go through the whole lineup in the first inning, that's not a good sign," Johnson said.