Twenty-five years ago when Paul McCartney organized the famed “Concert for New York City” to benefit the victims of and emergency responders to the Sept. 11 attacks, he included singer John Ondrasik, whose song about heroes, “Superman (It’s Not Easy),” was atop the charts, and seemed appropriate for the show.

Vladimir John Ondrasik III, born Jan. 7, 1965, is known professionally as Five for Fighting.

“Of course, I was very nervous,” Ondrasik says. “I’m a young guy who just got used to his song being on the radio. And I remember they had the itinerary of the show, which I hadn’t seen, and so I started at the beginning. It was a three-hour show; I expected it to be very early in the show, kind of with the younger bands, whatever.

“And I turn to the last page, and it’s, like, John Mellencamp, John Ondrasik, Janet Jackson, Elton John, Billy Joel and Paul McCartney. I’m like, ‘Oh my God.’”

Just three days before the 25th anniversary of that concert, Ondrasik at 8 p.m. Oct. 17 performs with a string quartet at Sellersville Theater 1894. Seating for the show is sold out, but standing-room tickets may be available by calling the box office at 215-257-5808.

This past September, Ondrasik was included in the “9/11 Tribute in Light” concert to mark the 25th anniversary concert at the foot of the Tribute in Light beams in New York City. He says he says he felt the same emotions he felt during the original concert 25 years ago.

“You might remember, most of those 20,000 people [at the original concert] had been down at Ground Zero, kind of wading through carnage, and none of them had had a chance to release their emotions,” Ondrasik says.

“But, you know, watching them sing and scream and hug each other and cry when I was playing ‘Superman’ … I locked eyes with this big union worker with two beers in each hand, and just tears running down his face, singing ‘Superman’ with me.

“It really kind of triggered me ... this kind of reality that sometimes music transcends in ways nothing else does. And, you know, in our business we talk about ticket sales and charts and hit songs and fame and fortune, and that’s part of our business.

“But that night, that moment, I think, really kind of stuck in my brain.”

After Five for Fighting played that original concert, ”Superman” became an anthem “to those who needed it most,” according to CBS-TV; spent 58 weeks on the charts; was nominated for a Grammy Award for Best Pop Performance, and the album on which it appeared sold platinum.

Five for Fighting has continued a long and successful career. His next album, 2004’s “The Battle for Everything,” also sold platinum, and the song “100 Years” sold even better, hitting platinum and No. 1 on the Adult Contemporary chart.

He’s since had nine more charting hits, including the Top 40 hit “The Riddle” in 2006.

Throughout his career, Ondrasik hasn’t shied away from addressing serious subjects in his music.

In 2021, he released the single “Blood on My Hands,” a song critical of America’s withdrawal of troops from Afghanistan and its foreign policy toward that country.

“Everybody’s like, ‘You cannot put that out,’ and I took a lot of heat from that,” Ondrasik said.

He said YouTube initially banned the video, “then they had to apologize and put it back up; it became, like, an international story.”

In 2022, Ondrasik released “Can One Man Save the World?” about the Russian invasion of Ukraine, and performed it in Kiev with the Ukrainian Orchestra.

And perhaps one of his most controversial songs was 2024’s “OK,” in response to Hamas’s attack on Israel and the rise in antisemitism that followed.

“I’m not somebody who, frankly, stands on my soapbox and lectures people about my politics or my views. I kind of disdain artists who do that,” Ondrasik says. “But at the same time, you look through history and people write about the world around them.

“Listen to my music from the last 20 years. I support the troops, I appreciate freedom, all that stuff. But Afghanistan kind of was the first kind of stepping out in a way where I knew I didn’t need names.

“I always say that if a different administration was in power and did the same thing, the song would remain the same. … Of course, that got a lot of push back. But it became a voice for Afghan veterans who felt gutted by the fact that we abandoned their allies. So it became a voice for them.

“And then Ukraine was a little different because, frankly, some of the people that really were mad at me for Afghanistan appreciated my Ukraine song, and some people that loved me for Afghanistan really didn’t appreciate Ukraine.

“But the big one was ‘OK.’ When Israel shared ‘OK’ on their social media, then the onslaught of hatred and death threats and all this stuff - that for whatever reason, you said, ‘Hamas is bad.’ That was something that still continues to this day, to the point where I have to have extra security at my shows.

“I look at these and I understand why people think they’re political. But in my mind, they’re simple moral issues. I mean, the Taliban is bad. You know, Putin is bad. Hamas is bad. And if I’m going to get heat for that, so be it.

“I think the music industry has lost its mind, frankly. But I kind of do my own thing, and I’ve … always been a misfit in the industry. And I think shining the light on Israeli hostages, the Ukrainian people and, frankly, African women who still can’t go to school years later and have been thrown into the dark ages that nobody talks about. I think those are important things.

“And I hope I don’t have to do another one. But in this world, who knows?”

With its piano foundation, Five for Fighting’s music has always had a classical foundation to its sound. But for the past 10 years, Ondrasik often has toured with a string quartet that offers his songs in a more formal presentation, as he will in Sellersville.

“I’m so blessed to have just incredible world-class musicians, both in the string quartet and the rock band,” he says. “And to go back and forth with [Five For Fighting guitarist] Pete Thorn and then [Tony Award-winning violinist] Katie Kresek and Tony winners, Broadway players, rock stars.

“And it’s just so inspiring to me to have this level of players, and also they’re just wonderful people. They’ve really become, when you do this for this long, they’re kind of like your second family.

“And so I think for me both are a joy, and the quartet shows are certainly different than the rock shows. They’re more intimate. I pull different songs from my catalog. Of course, it allows me to kind of branch out and kind of go deep in the catalog, and it’s much more of a storyteller show.

“And frankly, one of my favorite parts of the show is I exit stage left and I let them just jam for five minutes. We’ve done, what, probably 500 shows, and I don’t think one has not gotten a standing ovation. So you know, it’s pretty awesome.”

While “Superman (It’s Not Easy)” got renewed attention this year with the anniversary of 9/11, Ondrasik now is 61, and there seems reason to start comparing his life with his song “100 Years,” about milestones in life and “you’ve only got a hundred years to live.”

Late in the song it says, “67 is gone/The sun is getting high/We’re moving on” before the singer is “99 for a moment and dying for just another moment.”

“I say this every night: I wrote ‘100 years’ at the top of that second verse, you know, ‘33, family on my mind,’” he says. “I went through the midlife crisis verse, and I got that right. And now I’m in the bridge, and I like being in the bridge because the lyric is ‘suddenly you’re wise.’

“So I’d like to think I’m a little wiser than when I wrote it. And then, as you said, you know, one day I’ll be in the vamp, and one day I’ll hit that last note. But you know, that’s the way. That’s the way it should be, and I’m enjoying every every stage of of this.

“And hopefully, I’ll make it to the vamp. And you know, if for some reason, I get to 100 years and beat the song, you know, God bless me.”

Five For Fighting with String Quartet; opening: Lace & Lee, 8 p.m. Oct. 17, Sellersville Theater, 24 W. Temple Avenue, Sellersville. Doors open at 7:30 p.m. Seating sold out. Standing-room tickets may be available: 215-257-5808. Box Office: 10 a.m. - 5 p.m. Monday-Saturday; noon-5 p.m. Sunday; prior to show.