The teams of Matt Kuchar-Harris English and Charles Howell III-Justin Leonard also shot 64 on the Ritz Carlton Resort's Tiburon course. The 24 teams will play better ball Saturday and finish with a scramble Sunday.
After playing the front nine in 3 under, Perry and O'Hair birdied Nos. 13-16.
"It was a fun day for me," said Perry, the Champions Tour player of the year and Charles Schwab Cup points champion. "When (O'Hair) poured it in from about 15 feet on the first hole I knew it was going to be a good day for us. We were never in any trouble.
"We had a great chance to really go low today and better than 8 under, but that's OK. I mean, alternate shot is a tough format. To me it's my favorite format. I love it more than any format of all the three. So, you know, you can lose it. If we get off to a crummy start it's hard to catch up with best ball and scramble coming up."
Kuchar and English birdied Nos. 12-14 and eagled No. 17.
"Yeah, it was a lot of fun playing with Harris," Kuchar said. "I knew he was on some pretty good form and knew I had a good horse for a partner."
English replaced the injured Brandt Snedeker in the field
"This is a tournament that I've always watched on TV growing up and it seemed like such a great format and such a good competition," English said.
English hit a 6-iron shot from 192 yards to 6 feet to set up the eagle.
"When you start hitting some good shots and start getting some momentum, you keep rolling and we did a good job of keeping that momentum going on the back nine and making a bunch of birdies and making eagle on 17," English said.
Howell and Leonard birdied the final three holes on the front nine and added birdies at Nos. 10, 12, 13, 17 and 18.
"Today we chose Justin to hit first and that was great for me because he drove it in the fairway every time and I could swing away at it." Howell said.