Like most touring musicians, John Ondrasik’s main line of work was shut down due to the COVID-19 pandemic.

But the man who performs as Five for Fighting had plenty to keep him busy.

“I had to take over the family business for my father, who is 82 years old and quarantined,” Ondrasik said during a telephone interview.

The family business is manufacturing shopping carts, and those carts may be the reason people got to hear such Five for Fighting hits as “100 Years” and “Superman.”

“I was grateful to be able to repay my dad for supporting me when I was a musician,” he said. “I’d go to the family business, then I’d go to an audition. It was so instrumental in giving me the time to have this career. I broke late. I was in my late 20s, early 30s (when he signed a record deal). That never happens because people have to get jobs to be able pay rent and keep going. Being able to do this for him is paying him back for allowing me to have my career.”

But that doesn’t mean Ondrasik isn’t itching to get back out on the road. While he’s played some individual shows and benefits in recent months, the 12-city tour that brings him to Warren’s Robins Theatre is his first tour since the pandemic started.

“I’m so excited just to play, just to be together, to have an audience,” he said. “I never realized how much I missed it.”

On the current trek, Ondrasik will be backed by a string quartet. It’s a configuration he’s toured with off and on for the last five, six years and on the 2018 album “Live with String Quartet.”

“The last few years, I’ve done a lot of string quartet shows,” he said. “It’s so intimate. I think my audience, at this stage in my career, would rather sit down in a theater than stand up at a House of Blues. I can play the songs I wouldn’t necessarily play with a rock band.”

Many of those songs had string arrangements on the studio versions, often done by composer George Del Barrio

“I would bring him the songs that wouldn’t be on the radio,” Ondrasik said. “I was so excited going to his house to hear the mock-ups. My favorite day was going to Capitol Records and record the orchestra with George.”

The string players who accompany Ondrasik on the road are New York musicians who regularly perform with Broadway shows. Not only are they happy to be back to work, but they enjoy a performance that allows them to improv instead of strictly following the sheet music.

“The fact they aren’t rigid, they aren’t sitting down, they don’t have to wear a tux. They really make it their own and have so much fun. I get inspired just watching them jam.”

The format allows Ondrasik to play “Superman,” “100 Years,” “Chances,” “The Riddle” and other songs have earned Five for Fighting radio airplay and platinum album sales, but he has added some new songs since recording the live album.

“My wife insisted we change up the tour,” he said. “We have five new arrangements, including the song that got me my record deal. ‘Love Song’ is a song about divorce from the perspective of a child. That’s the song that launched me, got people interested in my music. It’s wonderful to play that with some strings. ‘Road to Heaven,’ that’s a great arrangement too, and we’ll have some surprises.”

If you go …

WHAT: Five for Fighting with string quartet

WHEN: 8 p.m. Sept. 23

WHERE: Robins Theatre, 160 E. Market St., Warren

HOW MUCH: $45 and $35. Tickets are available at the Robins box office and at robinstheatre.com.