The bearded 32-year-old signed for a four-under 67 around the Dunluce links at Royal Portrush as the Open returned to Northern Ireland for the first time for 68 years.
Lowry, who lives south of the border in Ireland's County Offaly, received loud support from the packed galleries but perhaps not to the same decibel-level as Northern Ireland's trio of major champions Graeme McDowell, Rory McIlroy and Portrush resident Darren Clarke.
Playing with former winner Phil Mickelson, who had a day to forget with a 76, Lowry posted a tough target for the later starters, collecting five birdies in his first 12 holes and going agonisingly close to more on 14, 15, 16 and 17.
Lowry wins British Open at Royal Portrush
Lowry, runner-up at the 2016 U.S. Open, has missed four successive cuts at the British Open since his best finish in 2014 when he was tied ninth at Royal Liverpool.
But he has put himself in a strong position to make a run.
"I thoroughly enjoyed today. The crowds are unbelievable and cheered on every tee box, and every green is such a special feeling," he told reporters. "I tried to enjoy that as much as I can while I was doing my work and then getting down to business.
It's going to be an exciting few days ahead. I hope I can give them something to cheer about on Sunday afternoon.
"I feel like for me I can come here a little more under the radar than the other guys. G-Mac is from here, he grew up here. Rory is an hour down the road and obviously had some great times here. And Darren lives here now."
Not that there were no butterflies on the first tee.
"Was probably as nervous as I've been in quite a while on the first tee, almost ever, I'd say," Lowry said.
Lowry signed for a four-under 67 around the Dunluce links at Royal Portrush
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"But nerves are a good thing, aren't they? It's where you want to be. I just hope I'm nervous on Sunday afternoon out there. It's right where you want to be, and you have to tell yourself that when you're there.
Where would you rather be? Would you rather be here or sitting at home watching on TV?
Lowry, who knows the Dunluce links well, said this year's Open could be one of the best. "It's got the potential to be an unbelievable Open," he said.
"Just hoping it's going to be special for me."
Clarke ended with a 71 after an early flurry of birdies while McIlroy had a horror start with a quadruple bogey eight at the first and McDowell struggled later in his round.
McIlroy: I want to punch myself
Rory McIlroy suffered a disappointing first day at Portrush
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Rory McIlroy said he felt like punching himself after suffering a nightmare round at the British Open on Thursday, shooting an eight over-par round of 79 at the Royal Portrush course.
The Northern Irishman started with a quadruple bogey eight on the par-four first after his opening drive from the tee flew out of bounds to the left.
But after grinding his way back to three-over, he imploded on the final three holes -- with some casual putting as he double-bogeyed the par-three 16th and then got in trouble in the rough to make a seven on the par-four final hole.
The 30-year-old four-time major winner was tipped as one of the favourites for the first Open in Northern Ireland since 1951 but now faces a battle to get back amongst the leaders. He said:
I would like to punch myself. I made a couple of stupid mistakes. I was pretty nervous on the first tee and hit a bad shot.
I showed some resilience in the middle of the round and was trying to fight back into the championship but then I finished off poorly as well.
"But seven over par combined on the first and last holes makes it very hard for you," he said.
McIlroy, who shot to prominence with a course record 61 at Portrush when he was a 16-year-old, rejected the idea that he had been impacted by the sense of occasion as the Open returned after a 68 year absence.
"At the end of the day I play golf to fulfil my ambitions not anyone else's but I wish I could have given the crowd something to cheer about," he said. "I let myself down more than anyone else and need to pick myself back up."
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