Hubert Green, who won this event in 2000, finished three shots off the pace alongside Gil Morgan and Ed Dougherty at 5-under-par 67.
North had no problems at TPC at River's Bend en route to his best round of 2002. He earned his first birdie of the day at the par-4 third and hit a pitching-wedge to 10 feet at the par-3 seventh for another birdie.
The two-time U.S. Open winner added an eagle at the par-5 eighth to make the turn at minus 4.
North continued his fine play on the inward nine with a four-foot birdie at the par-5 11th. He knocked his second shot to 10 feet for birdie at the 15th and drained a 35-footer for birdie at No. 17.
The 52-year-old found a bunker at the closing par-5 but recovered with a birdie to complete a bogey-free round.
'A good solid round today,' said North. 'Today was a perfect day to play. It's always nice to get off to a good start.'
North is looking for his first Senior Tour victory since he joined the circuit in 2000. The television golf analyst was the runner-up at the 2001 Emerald Coast Classic and earned his first top-10 finish of 2002 at the 3M Championship in August.
'I think my television work has helped me,' said North. 'The last month I started hitting the ball better. I feel I'm on track and hit some good shots. I'm very encouraged.'
Gilder, who has been one of the hottest golfers on tour with three victories since July including last week's Allianz Championship, started with three birdies on the front nine before the shot of the day at the par-3 12th.
The 51-year-old hit an 8-iron off the tee and the ball found the cup on the fly.
'I didn't realize until we walked on the green,' said Gilder.
Gilder birdied the last to match Smith, who had taken the early clubhouse lead with a 66 of his own. His round featured a stretch of five straight birdies starting at the par-3 fifth.
Jim Dent, who captured the inaugural event in 1990, carded a 4-under-par 68 to finish in a tie for seventh. Dent was joined by 1996 winner Isao Aoki, Dana Quigley, Allen Doyle and John Harris.
Tom Kite, Don Pooley, Jim Colbert, Bruce Fleisher and Larry Nelson share 12th place at 3-under-par 69.
Defending champion Jim Thorpe finished one shot further back at 2-under-par 70.
Full-field scores from the Kroger Senior Classic