The trio matched the course record at The National Golf Club of Kansas City on Friday. Pat McDonald and defending champion Jay Sigel established the original mark in last year's event.
Morris Hatalsky and 1999 European Ryder Cup captain Mark James share fourth place at 6-under-par 66.
Bean flew out of the gate on Friday with five birdies in his first six holes. He sailed over the green with his second at the seventh and failed to get up and down for par, but birdied the final two holes for a front nine of 6-under 30.
On the second nine, Bean sank a 12-foot birdie putt at the 12th and two-putted from 35 feet for birdie at No. 15. Bean was cruising at 8 under par, but made a mess of the par-3 16th and took double bogey.
He saved par from 10 feet at the 17th, then rolled home a 4-footer for birdie to post his third straight round in the 60s and share the first-round lead.
'There was not much stress in the round,' said Bean, who shared the 36-hole lead last week, but was forced to withdraw before the final round after an allergic food reaction. 'Today was one of those rounds you enjoy playing.'
Harris also made a quick start with a 12-foot birdie putt at the first and a 20-foot eagle at the second. He added two more birdies on the front side for a 31.
Harris collected three birdies in a row on the back nine, including a pair of 3-footers at 14 and 15 and a 20-footer at No. 16. He three-putted for a bogey at No. 17 to fall out of sole possession of first.
'I'm pleased with my round,' said Harris, whose 65 marked his best round on the Champions Tour. 'I got off to a dream start with birdie-eagle. It wakes you up and gets you going.'
Doyle was flawless on Friday with three birdies in his final four holes on the front side, the back nine at The National Golf Club. He missed a 6-foot birdie try at the par-5 second, but recorded three birdies in a row from the third, including a chip-in birdie at No. 4.
The 1999 champion knocked a 7-iron to 3 feet to set up birdie at the seventh. Doyle missed the green at the eighth, but chipped to 6 feet and drained the par save to keep his bogey-free round alive and stay atop the leaderboard.
'Obviously, I had a good day,' said Doyle, who hit all 14 fairways on Friday. 'I played a round of golf under control today. I was driving the ball well today and I tried to attack pins.'
Bob Gilder, David Eger, Vicente Fernandez, Jerry Pate, Jim Ahern and two-time winner this season Bruce Fleisher are tied for sixth place after opening with rounds of 5-under-par 67.
Sigel carded an opening-round 71 on Friday.