The German star, a two-time winner this year on the Champions Tour, had a 10-under 134 total on The Hills Country Club course.
Its better to be ahead than behind, Langer said. It was tough today, but winning always breeds confidence for me.
Gene Jones (66) was second, Jeff Sluman (69) and Mark OMeara (69) were 7 under, and Jay Haas (68), Scott Hoch (69) and local star Tom Kite (70) were 6 under.
Langer had five birdies and two bogeys, reaching 10 under with a 10-foot birdie putt on the par-5 17th hole on the Jack Nicklaus-designed course.
If we play decent, it will be hard for somebody to catch us, Langer said. If we play garbage, then anything can happen.
Jones, seeking his first Champions Tour victory, had seven birdies and one bogey. He birdied the par-3 18th, hitting a 6-iron to 3 feet.
Hes the best we have out here, but if you going to win for the first time, you might as well beat the best, Jones said about Langer.
OMeara also is winless on the 50-and-over tour.
It will happen eventually, OMeara said. I have a lot of peace in my life now and Im playing well so maybe Ill win this week to cap everything off.
Bobby Wadkins withdraw after the fourth hole because of back spasms. He began the round eight shots behind Langer.