Hale Irwin and Jim Dent were second, and Tom Watson, coming off a playoff loss last week to Tom Kite in the SBC Senior Classic, topped a group of eight players at 68.
Watson had his 12th straight round of par or better, the longest streak on tour this year. He has not had a round over par in five events.
Doyle, the winner two years ago when the final round was rained out, became the first player to hold the lead alone after the first round in Toshiba Classic history.
'I feel confident when I come here,' said Doyle. 'I hit irons pretty well, and you have to do that here.'
Doyle bogeyed the par-5, 510-yard 18th hole after recording six birdies and 11 pars.
'I was a little frustrated at 18 because you want to finish strong,' he said. 'But it was a good day other than that'
Doyle put his tee shot at the 18th close to a bunker down the left side of the fairway. Unable to take a proper stance, he hit the ball only 10 feet down the fairway on his second shot.
'I hit my drive into the rough and didn't have much of a shot,' he said. 'I hit a 3-iron on my third shot and an L-wedge that left me a 6-foot putt for par. I thought I had hit a good putt, but it just rolled off line.'
Irwin, who won the Ace Group Classic last month in Florida for his record 33rd senior title, birdied three of the first seven holes en route to his bogey-free round.
'I didn't play badly,' he said. 'I just didn't feel like I putted great. I had one of those days where I had a better score than how I played.'
Irwin missed birdie putts of 8 feet at the ninth hole, 10 feet at the 10th, and 6 feet at the 11th.
'A really good score got away from me in the middle of my round,' he said. 'This is a great start considering that I have not gotten off to a very good start the last couple of tournaments. I'm a lot more comfortable that I can carry that momentum into Saturday and Sunday's rounds.'
Sammy Rachels had the first hole-in-one in tournament history, acing the 167-yard 13th hole with a 6-iron. It was the sixth hole-in-one of Rachels' career. He finished with a 70.
Kite withdrew because of back spasms. He attempted to warm up before the start of the round, but was unable to continue.
Kite, a two-time winner and the tour's money leader with $608,600, had been having back spasms the last two days. He leads the Charles Schwab Cup race with 606 points.