Oliver Bjorkstrand scored two third-period goals for Columbus (13-14-6), which is on a four-game point streak (2-0-2), including a 5-2 win at Washington on Dec. 9.
Korpisalo has three NHL shutouts, including Nov. 25 in a 1-0 win against the Ottawa Senators.
"He looks confident, doesn't have any extra motion, and has put up some good numbers for us here," said Blue Jackets coach John Tortorella, who passed Darryl Sutter for 15th in coaching wins in NHL history with his 635th.
WATCH: [All Capitals vs. Blue Jackets highlights]
Braden Holtby made 18 saves for the Capitals (24-6-5), who lost on the road for the first time in six games. Washington has won eight of its past 10, the two losses coming against Columbus.
"We were second on pucks. Slow," Capitals forward Lars Eller said. "Poor execution when we had the puck, as well as lack of attention to detail."
Korpisalo praised his teammates.
"They did a great job blocking shots, using their sticks," he said. "I have to make some saves there too."
In four games against Washington, Korpisalo is 3-0-0 with a 1.08 goals-against average and a .966 save percentage. He made 37 saves in the Dec. 9 victory.
"He's played really well the two games against us (this season)," Capitals coach Todd Reirden said. "We've got to find a way to get in front of him some more, get more into the interior, and make things more difficult for him."