Jack Antonoff details how the death of his sister shaped his songwriting

Jack Antonoff is opening up about how he's used songwriting as a coping mechanism to process loss.

The musician sat down with Willie Geist for the Oct. 15 edition of Sunday Sitdown and reflected on his journey in the music industry.

“My whole life, I had written about my sister," he told Geist.

When he was 18 years old, Antonoff's younger sister Sarah died of brain cancer. She was 13.

This experience shaped most of the songs he's written, he said.

“I kind of wrote pretty much about that loss through the lens of different ages, which is a really powerful place to write from,” he told Geist.

His early focus on music can also be attributed to the impact of his sister's illness on his family, he said.

“I didn’t grow up with a lot of social norms because my parents just felt like they were frying a bigger fish” he continued. “Because she was sick — in a great way, they just didn’t care.”

"Do what you want to do" described his parents' attitude toward his pursuit of music, Antonoff said.

When asked what sparked his initial interest in music, Antonoff couldn't pinpoint something specific.

"I don’t know," he told Geist. "I just always wrote, and I always played. And it was when I was doing all of it that I could really recognize myself the best."

But Antonoff's upcoming record, Bleachers' fourth studio album, has a "different feel to it," Geist noted.

He credited his band’s growth and his marriage to wife Margaret Qualley as things that helped create "real armor" for him as he started to write with a new inspiration.

“I felt like I could, for the first time, write a little bit outside that lens. It’s just way more present than I’ve ever been," he said.

Before Bleachers, Antonoff also served as the guitarist for Fun, the band behind radio hits like "We Are Young" and "Some Nights."

But the band started as a "side project" for Antonoff and two of his friends. Its rapid success made the project "stresssful," and eventually in 2015, Fun went on hiatus, where it remains today.

It was around that time when Antonoff got his start producing. He said the first person to give him the thumbs up to formally produce a work was none other than Taylor Swift, now his friend of nearly a decade and who he's previously called his "favorite collaborator."

When asked about the magic behind his friendship with the “Anti-Hero” singer, the New Jersey native joked, “She vacationed on the Jersey Shore, I think, when she was a kid."

Swift notably attended Antonoff's wedding to Qualley this past August.

"When we’re in a room together, it’s just, it feels like this crazy blend of, like, two kids in a room, two old professors in a room. Two teenagers in a room," he said.

The Grammy award winner says his next era is defined by a goal to “chart new spaces, and try new things,” something he feels able to do in part because of the people around him.

"It’s really, really hard when you have an entire industry of people telling you, 'You’re never gonna work again unless you do that again,'" he said. "Unless you can find those rare — I’m lucky, I have them — those rare, rare people who just really light a fire in you to continuously find yourself over and over and over again at wherever you are in life."

This article was originally published on TODAY.com