Michele Redman is alone in second place at 8-under par, followed by Danielle Ammaccapane and Jackie Gallagher-Smith, who share third at minus 7.
Sorenstam, already a three-time winner on the LPGA Tour this season, did not need long to get acquainted with Stonebridge Country Club. She opened with birdies on her first three holes, all on putts from inside 12 feet.
The Swede took a break from making birdies with a par at No. 4, but got right back on track at the fifth. She drained a nine-foot birdie putt there, and then made birdie on her next three in a row, giving her four consecutive birdies, with each putt from around six feet.
After her birdie at eight, Sorenstam admitted that she was thinking 59. She has experience with the score, as she is the only player in LPGA Tour history to fire that magic number, when she did it in the second round of last year's Standard Register PING.
'When I made the putt on eight, I had goose bumps everywhere,' said Sorenstam, who won her second consecutive Nabisco Championship earlier this season. 'I tried to stay patient, but my mind was wandering everywhere. I was thinking I've got seven or eight holes left and only need five birdies. But, I tried to hit one shot at a time. The ball doesn't know how many under you are, so you just keep hitting it.'
Sorenstam collected another birdie at the 10th, but went cold with five pars in a row. She three-putted from 12 feet for a costly bogey at 17, but took sole possession of first place with a four-foot birdie putt at the last.
'I felt so good about my game, the way I warmed up and everything,' said Sorenstam. 'It felt very similar to the day I shot 59 in Phoenix. I played really well and hit some really good shots. A 63 is good any day though. I just want to continue on, keep going and see how many birdies I can make.'
Redman, winless since 2000, was flawless Friday. She tallied five birdies on her opening nine, the back nine at Stonebridge, and thanks to sharp iron play, the longest birdie putt she made was from 12 feet.
On her second nine, Redman birdied one and four and played a 9-wood to six feet at the seventh to set up birdie and reach 8-under-par.
'Honestly, my wedge game has not been as good as it has been,' said Redman. 'I put my original wedges back in my bag, but I can't believe how much better I'm hitting it.'
Suzanne Strudwick and Carri Wood share fifth place at 6-under-par. Ten golfers are tied for seventh at 5-under highlighted by 50-year-old Jan Stephenson.
Karrie Webb returned to competitive action this week and is in the hunt after an opening-round 68.
Laura Diaz, last week's Corning Classic champion, struggled in her first round. She posted a 4-over 76 and is tied for 135th.
Full-field scores from the Kellogg-Keebler Classic