Played opposite the Scottish Open, the event is sanctioned by the PGA Tour and the European tour. The winner will get into the PGA Championship but not the Masters next year.
The 46-year-old Glover had a 13-under 127 total at Hurstbourne Country Club, playing through rain in the morning on Friday.
"It was a little bit nasty this morning when we started, had some rain through the first few holes," Glover said.
"Played nice, solid, no bogeys through two days. Need to keep that up. Scores are going to be low, so keep the pedal down."
Chan Kim (65) and Steven Fisk (66) were tied for second. Aaron Wise (65) and Jeong Weon Ko (65) were another stroke back at 10 under. Defending champion William Mouw was nine under after a 63.
"I played really solid golf today," Mouw said. "Hit my targets, had really good speed on the greens. Short game held up when I missed a green. All in all, very pleased with my round today."
Glover, the only major champion in the field, has six PGA Tour victories, highlighted by the 2009 US Open. He tied for third last week in the John Deere Classic.
"I had a feeling it was going to be soft today just with the forecast and everything," Glover said.
"Just stay aggressive. Came out a little early after the delay to make sure I had the speed of the greens. They were a tick slower, but nothing drastic."
NCAA champion Preston Stout was five under after a 67. The Oklahoma State senior tied for 15th in the John Deere.
Former Auburn star Jackson Koivun had a 68 to also get to five under. He missed the cut last week in his professional debut.
Australians David Micheluzzi (one under) and Josiah Gilbert (even par) missed the three-under cut.
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