Playing only the third major of his career after securing his place by finishing second at the US PGA Championship last year, Lynn carded six birdies and two bogeys to set the early clubhouse target.
And although he was subsequently overhauled, the world number 53 could have no complaints after a round which saw him finish ahead of more high-profile compatriots Lee Westwood and Justin Rose, who were both round in 70.
The 39-year-old from Stoke, who has just one win in almost 400 European Tour events, birdied the first, eighth and ninth to be out in 33, and after a dropped shot on the 10th, hit back with birdies on the 11th, 12th and 15th.
A bogey on the 17th looked like being followed with another on the 18th when he was faced with a 12ft putt for par after hitting his approach over the green, but he holed out to complete a brilliant debut round.
"Everyone said playing here was about the percentages and talking to an old friend of mine, David Gilford, who came here for the first time and shot a 67 in the first round, he said 'Don't be too intimidated by the greens. There are birdies out there,'" Lynn said. "So I had that in my mind as well.
"I was on the ninth and my caddie said 'You're leading the Masters.' He just looked at me and smiled. I said 'I'd rather be leading it Sunday afternoon' but it's obviously not a bad thing to see your name up there and something you could always look back on.
"But there's a lot to be done for the rest of the week and hopefully I can keep my name up there.
"It's taken me a golfing lifetime to get here. You do feel like you know the place, because you see it that many times on TV. It's fantastic."
As for Wigan's FA Cup semi-final with Millwall on Saturday, Lynn added: "I'd love to see Wigan progress into the final. I would love to see them survive a ninth year (in the Premier League) and if they can bring home an FA Cup that would be fantastic."
Lynn had not planned to move to the United States until his performance at Kiawah Island last August opened so many doors.
And although he is not certain of staying, he admits it has given his career a new lease of life.
"It's given me a second wind at the moment," he said. "Obviously everything's new. I'm going to a different place every week, a different course, and it's like I've started my career again almost.
"I'm having to knuckle down and do my homework when I get to places, and am just enjoying what the PGA Tour has to offer at the moment.
"When I am on my game I know I can compete at this level and Kiawah Island (for the US PGA) confirmed it to me. It gave me a bit of extra belief. I'm not going to sit here and say I'm going to be there Sunday night, but deep down I know that I've got performances in me that could put me there Sunday night."