‘Mamma Mia’s’ leading lady landed her first Broadway role in the show while she was teaching 5th grade

This time last year, Christine Sherrill was teaching fifth graders American history in Kenosha, Wis.

Now she’s making Broadway history.

The 54-year-old actress and teacher is playing Donna in “Mamma Mia!” at the Winter Garden Theatre.

When she got the news she’d landed the role, she had just finished teaching a unit on the American Revolution, where she used the musical “Hamilton” as source material.

“I had a lot of boys in my classroom and they were all athletes. So when I introduced ‘Hamilton’ to them, I was like, ‘This is going to be a chore.’ And they were glued,” Sherrill told The Post.

“I would get feedback from parents being like, ‘I’ve never heard my kids sing before and we’re making dinner and they know all the ‘Hamilton’ lyrics.’”

So when she announced to the class that she would be leaving for Broadway, “they were like, ‘Are you gonna be in ‘Hamilton?!’”

She auditioned for “Mamma Mia!’s” leading lady in March, when she took a Thursday off from Saint Joseph’s Catholic Academy to fly to New York for a long-shot audition.

The next morning, “I went back to school like nothing ever happened. I literally had to let it go. I was like, ‘There were so many women there that are incredibly talented. This is not for the Wisconsin teacher,’” she said.

But it was. And with good reason.

The Chicago native with a master’s degree in education always had talent and was actually discovered by director Marc Robin in 2001 while performing at Pheasant Run Dinner Theatre outside Chicago, where actor Sean Hayes also got his start.

“I was singing at night for extra money because we all know how much teachers make. And he saw me and was like … ‘How come I don’t know you?’” she recalled.

“I’m so grateful to him that I actually sent him flowers on our Broadway opening night.”

She taught for eight years while also working as an actress — reluctant to give up her day job.

“I needed the stability and was afraid to leave teaching. Since being out of college, I’ve gone back and forth between two careers. So I was an actor in Chicago regularly, and then I would go back to teaching, and I was always a tutor,” she explained.

“I had gotten quite a few calls from my agents about other auditions, and nothing really seemed to be enough to pull me out of teaching.”

That all changed when she learned that “Mamma Mia!” was headed back to Broadway.

Sherrill’s history with the beloved musical dates back to 2006, when she toured with the show in another role.

She first played Donna — the single mother whose daughter invited her three possible fathers to her wedding — on tour in 2014 and again in 2023. She estimates she performed in the show 3,000 times.

Meryl Streep famously played Donna in the 2008 movie version of “Mamma Mia!,” but since the A-lister hasn’t come to see the show yet, Sherrill has another favorite celebrity audience member.

“Jean Smart. She’s come twice. She came to see us in L.A.. And then she came to see us here. She always sends notes and stuff. She’s just one of the coolest people ever.”