For close to a decade, Keith Harkin juggled two parallel music careers.

The Irish singer-songwriter (and as of May, a father) was best known as the lead singer for Celtic Thunder, a singing group/touring stage show that combined elements of traditional Celtic music and dance with theatrical production, from 2007 to 2016. During that period, Harkin also toured behind his first two solo albums (2012’s self-titled effort and 2016’s “On Mercy Street”), which took a grittier Americana approach than the polished pop leanings of Celtic Thunder shows.

“I was trying to leave Celtic Thunder for a long time, and the time was right just to leave,” Harkin said recently while on the way to a show in Calgary, Canada. “Because the touring was getting too much — I was touring with those guys full time and then touring myself full time — I was just tired doing it.”

Harkin, who returns to Bend to play a solo show at the Domino Room on Monday, has focused solely on his own music for the last 3½ years. He said he is grateful for the playing experience he received in the group, as well as for songs he contributed to the show such as “Lauren & I” (still a staple of his solo sets).

“Celtic Thunder is a show, and we were paid to play parts in a show,” Harkin said. “It’s like if you’re going to watch any big production on Broadway, people (are) paid to play a part. … That’s basically what Celtic Thunder is. It’s not like a band; they’re not performing their own songs every night. But I was playing the part, but I was lucky enough to also write some songs for the show, as well, which was amazing.”

But he clearly has moved on from the group. Since leaving, he released a Christmas album, 2016’s “Nollaig,” and last year’s “In the Round,” an acoustic live album featuring guitarist Dave Bakey. The latter featured new single “Mercy,” one of a number of songs Harkin collaborated on with Eagles songwriter Jack Tempchin.

“Jack just released an album about two or three weeks ago (‘One More Time With Feeling’), and the first track on his new record is a song called, ‘One of the Good Old Days,’ and that’s a song Jack and I wrote together,” Harkin said. “He also just got inducted into the (Songwriters Hall of Fame) about a month and a half ago — himself, Cat Stevens and John Prine got inducted on the same night. So it’s pretty cool to have a song on someone of that caliber’s record.”

Harkin also has plenty of new music in the can or ready to be recorded, including a follow-up Christmas EP that should be released sometime around Thanksgiving, he said.

He will also team up with pop/rock singer-songwriter Brett Dennen and Austin Jenkins, who co-wrote Leon Bridges’ Grammy-winning single “Bet Ain’t Worth the Hand,” for his next solo album, which he plans to record in October at his studio in Ireland.

Before that happens, Harkin will spend time digging through his past. He is touring behind his latest release, “10 Years Later,” which was recorded a decade ago with his band at the time, The Durty Stopouts. The album’s raw feel stands in contrast to the more polished sound of his self-titled effort and “On Mercy Street.”

“The reason why I never released it was because I signed to Verve Records,” Harkin said. “You know how record companies are. They want their own albums, and I just recorded the record about a few weeks before I signed a major record deal. So they wanted to do a whole new project. So I was like, ‘Oh, I’ll release it next year,’ and then another project grows, and I was like, ‘Oh, I’ll put it right after that.’ And just — it was 10 years later, and I was like, ‘I have to put this record out.’”

The album’s songs all feature former Paul McCartney and Wings guitarist Henry McCullough, who adds grit to Harkin’s country- and Americana-leaning songs. Engineer Enda Walsh, who has worked with Van Morrison and also owns Amberville Studio in the U.K., where the album was recorded, introduced Harkin to McCullough.

“Enda’s a good friend of mine, and he’s been a studio mentor for me; he always helps me out building my studio and stuff like that,” Harkin said. “He was good friends with Henry; they’d been in the scene together in the same sort of area for a long time. He basically said to Henry, ‘Look, I’ve got a kid down here who’s playing some cool music, and I think you would dig it; do you want to come down and play on it?’ And Henry was only supposed to play on three of the tracks, but when he came down he loved the whole album and recorded on the entire record for me — I didn’t even have to ask him.”

Having a 4-month-old child has made touring a little more difficult, he said. He and his family split their time between Los Angeles and Ireland.

“I don’t sing the songs for me anymore,” he said. “I sing them for my kid, simple as that.”