Wadkins is tied with J.C Snead and Joe Inman for the top spot. Jay Sigel and Steve Veriato are one shot back after a pair of 6-under 66s.
Defending champion Bruce Fleisher opened in 69.
Wadkins, who turned 50 on July 26, is winless in 777 career-combined starts on the PGA and Buy.Com Tours.
Friday at the Meadow Brook Club, Wadkins carded eight birdies and one bogey. After making the turn in 1-under 35, Wadkins birdied hole Nos. 10, 12, 13, 15, 16 and 17.
'If I putted like that on tour for 27 years, I wouldn't need any sponsor's exemptions,' said Wadkins.
'I was a little pumped up on the first tee...I teed my ball up and felt fine then I had the kind of reaction I had at my first Masters. I could see my legs moving and my pants shaking and I knew I was pumped up and it's the first time in a while I've had that adrenaline working and I think it worked to my advantage.'
Bobby's older brother, Lanny, won in his first Senior start, the 2000 ACE Group Classic.
Full-field scores from the Lightpath Long Island Classic