Jonathan Quick stopped 19 shots for the Kings.
After two scoreless periods during which the Kings outshot the Stars 30-15, Jagr finally got his team untracked. He scored his team-leading 12th goal at 6:34, taking the puck wide and holding it before shooting and watching it bounce into the net.
"It felt like we had enough shots, just didn't bury our chances," Los Angeles' Kyle Clifford said.
Whitney made it 2-0 at 10:56, beating Quick stickside for his fifth goal.
"I'm not even sure where it went in, whether it went above or under him," Whitney said. "He is fast, for sure, and he anticipates the play pretty well, so I wasn't trying to pick a corner or anything. I was just trying to hit the net, and I guess I was fortunate he didn't get it."
Whitney extended his point streak to five games, with three goals and three assists. He returned earlier this month after missing 16 games with a foot injury.
"Not many guys in this league can hold the puck and wait for the guys to come into the play late, but he's able to do it," Jagr said. "He's got the quickness and he's got big legs, so he can skate, and when you look at him, he's always moving. That's what makes him very dangerous. He hits the net all the time and doesn't miss very often. Young guys should learn from him."
NOTES: President Barack Obama will honor the Stanley Cup champion Kings and MLS Cup champion Los Angeles Galaxy at the White House on Tuesday. ... Whitney turns 41 in May. ... The Kings had won 11 of 12 at home since Feb. 15, with their only loss in that span against the Stars. ... The Stars improved to 2-4-0 in the second game of back-to-backs, having lost 4-3 at Colorado on Wednesday after blowing a third-period lead.