The 32-year-old carded a four-under-par first round of 67 at Royal Portrush to move one shot clear of a group of five players.
But Lowry admitted that he felt the pressure early on.
"I felt uncomfortable on the first tee, I was glad it was downwind so it was only a three iron," he said.
"It's the British Open, it's in Ireland. I feel like I'm hitting it well. Of course I feel uneasy.
"Nerves are a good thing... I hope I'm nervous on Sunday afternoon, that's where you want to be. You have to ask yourself if you'd rather be there or sat at home watching on TV."
Organisers expect the second-biggest attendance in Open history this week, with 237,750 fans estimated, and the locals lent strong support to all six players in the field from either the Republic of Ireland or Northern Ireland.
Lowry paid them back in style, making five birdies in the slightly easier morning conditions before the predicted heavy rain in the afternoon.
"I thoroughly enjoyed today, the crowds were unbelievable, I was cheered on at every tee box," he said.
"I stand on tees and scan the crowds and see a few familiar faces.
"It's going to be an exciting few days ahead and I hope I can give them something to cheer for on Sunday afternoon."
Lowry has contended at majors before, finishing runner-up to Dustin Johnson at the 2016 US Open.
He slipped to 92nd in the world rankings last year, though, before a string a strong results -- including victory in January's Abu Dhabi Championship -- saw him climb back to his current mark of 33rd.
"I feel like if I hit a bad shot I can get myself out of trouble. That's a good place to be in," Lowry added.
"It would be great to contend this week but it wouldn't be the end of the world if it doesn't happen.
"I'm a bit more under the radar than the other guys... But obviously not here."
One home hope who did not manage his nerves on the opening hole was pre-tournament favourite Rory McIlroy, as the four-time major winner made a quadruple-bogey eight.
"I did hear about that. I don't have much to say about that, I feel for him," said Lowry. "Obviously he's one of the best golfers in the world."