Justin Clancy was in the bathroom, about to depart for a tour, when he got the news he had been waiting years for — he was going to play Boston Calling.

The Peabody native joins an impressive lineup for the festival including Ed Sheeran, the Killers, and Hozier. Clancy admitted that he “freaked the (expletive) out” when he got the news.

“It was definitely gratifying for sure,” he told The Item in an interview this week.

But, Clancy said he had already spent years telling himself he would make it to the festival stage, and doing so was just a matter of time. As a result, Clancy said he felt as though he had already had the experience of performing.

Still, cracking the festival lineup was a major milestone, he said.

“It’s one of the… Boston Infinity Stones,” Clancy said. “It means a lot to me because I started out doing (expletive) little shows in basements for four or five people. Being able to build it out brick by brick and have it unfold right before my eyes, it’s kind of surreal, but at the same time, it’s just proof that energy and persistence… always pays tenfold.”

Clancy isn’t reveling in the news, though, already turning his attention to what might be next.

After all, Clancy’s career has grown tremendously in recent years. His music has racked up millions of listens on Spotify and the streaming service reports he has nearly 23,000 monthly listeners. He attributes some of that success to his ability to avoid becoming complacent.

“While I’m extremely grateful for the opportunity, and I’m really excited, it’s not going to be the summation of my whole entire career, nor is it going to be the peak,” he said. “It’s just another notch in the belt.”

Clancy said it’s difficult for him to take a step back and revel in his success because doing so can become overwhelming.

His journey to Boston Calling began on the top bunk of a halfway house with nothing but a trash bag full of clothes, when Clancy was looking at potential jail time. Clancy, who has been open about his struggles with addiction in his music, said the vulnerability he displays is what has led to much of his success.

“I was on an island… in British Columbia… and people knew who I was and knew the words to my songs. That kind of stuff is absolutely mind-blowing,” he said. “I try not to get too caught up in it because it’s so much bigger than me,” Clancy said.

“The music is just a vehicle,” he added.

At Boston Calling, Clancy will perform during the first day of the three-day festival, which takes place over Memorial Day weekend. His set will run approximately half an hour, and Clancy said he feels he’s performing on the best day of the festival.

But beyond that, he said he remains largely in the dark about what exactly the day will entail.

In fact, Clancy said he had no idea who else was part of the lineup for the festival until the day it was announced to the public. Clancy admitted keeping the secret of his own appearance was a challenge.

“It was definitely difficult to keep the secret for sure,” he said. “(But) what mattered most was that I was (in) it. And I was able to say that I’m going to be playing it. The rest is subjective.”

“It’s all bonus points,” he added.

Clancy acknowledged the sheer difficulty of breaking into music, saying “it’s the hardest industry in the whole entire world.” He said he was able to break through on the basis of sheer determination and consistency.

“At the end of the day, they’re never gonna kill me,” he said. “This industry and this world is going to try and kill you.”

“They’re gonna take every single thing from you. It’s going to be the most difficult thing that you’ll ever do, ever, but I stick with it because they can’t stop me,” Clancy added. “Nobody can stop me but me.”

By cutting his teeth in the underground rap scene, Clancy learned quickly that hustle and hard work are essential to success. As he moved into alternative and pop, that mentality has been a boon, he said.

But even beyond music, Clancy credits the North Shore with helping him develop.

“It’s a blue-collar hard-working neighborhood. That’s just how it’s always been,” he said. “We have tough skin and we keep pushing no matter what.”