When most people think of the Pope, they envision him in gilded buildings at the Vatican or making appearances on a velvet-covered balcony, not attending a student concert conducted by Latin School band teacher Cynthia Gradek. But long before he was Pope Leo XIV, Robert Prevost was a crucial part of the St. Rita of Cascia community on Chicago’s Southwest Side, where Ms. Gradek first met him.

St. Rita High School is run by the Augustinian Order, a Catholic church order devoted to education, evangelization, and pastoral care. In her 23 years of teaching at St. Rita, Ms. Gradek often attended mass run by the then-Father Prevost, who led the Midwest Augustinians at the time.

“Whenever he would come back to town, he would do a mass for the entire school community, and he would talk about his time in Peru and his mission work,” Ms. Gradek said.

Her role as a band teacher at St. Rita later led her to take three trips with her students to Italy, when the group would meet up with Prevost, who was a bishop at the time. As Ms. Gradek added, he even attended one of their band concerts.

Ms. Gradek’s most recent memory of the newly elected Pope stems from a pilgrimage to Italy and Greece last summer. She was accompanied by 30 or 40 others, many of whom were Augustinian priests she had befriended at St. Rita. Ms. Gradek reflected on how a simple interaction with Prevost—who had recently become Cardinal—during the trip would prove impossible today, given his role as Pope.

“A lot of people didn’t know him, but I knew him from how many times we’ve met,” she said. “And I said, ‘Oh, there he is, he’s walking down the street.’ And when he was standing on that balcony as the Pope, I thought, ‘Oh my goodness, he can’t just walk down that street anymore’; his whole life had changed completely.”

She further recalled a heartwarming conversation she had when Cardinal Prevost took the group to visit the back lot of St. Peter’s Basilica.

She said, “Cardinal Prevost was just standing there by himself, and I went off to him to reintroduce myself. He knew exactly who I was. He said, ‘How’s the band doing?’”

Both during her time at St. Rita and through some of her more recent interactions with Prevost, Ms. Gradek watched his transition throughout the ranks of the Catholic Church. To her, his election as Pope was a long time coming.

“I’ve been telling people since he became Cardinal [that] if America ever gets a pope, it’s going to be him,” she said. “Part of me believed that it [was] a long shot, but if anybody should be Pope, it should be this guy.”

On May 8, Ms. Gradek’s wishes came true, as Pope Leo was announced as Pope Francis’ successor. In a band room filled with excited fifth-grade students, she watched this history unfold in real time. The fifth graders, who had come in during recess to prepare for their upcoming concert, began to grill her about the significance of the conclave, which she had projected onto the room’s Smart Board.

After explaining the logistics of the conclave, Ms. Gradek offhandedly mentioned that she knew one of the candidates, though she doubted that the cardinal electors would select an American. The curious fifth graders asked Ms. Gradek for her “friend’s” name, which she gave to them, not knowing the next moment would be nothing short of memorable.

“They come out, and they’re announcing it in Italian, and you hear Roberto Prevosto, and I’m like, ‘Oh, my God, that’s my guy,’ and [the fifth graders] went crazy. They were honking their horns; they were standing on their chairs; they were just celebrating.”

She continued, “It was time to go back to class, and the new Pope had not stepped out on the balcony yet. [The fifth graders] were like, ‘Please, can we wait and see him?’ So we sent an email to their teachers that they would be a little bit late, and when [Pope Leo] came out, they were just cheering.”

Fifth grader Conley Kutschke said, “I thought, ‘Oh my goodness, Ms. Gradek is so happy. This is awesome.’”

He added, “[Pope Leo’s election] makes Ms. Gradek half famous and I’m lucky to know her, someone who knows the Pope.”

Ms. Gradek appreciated her students’ enthusiasm. “It was just so neat that these students of different religions and different backgrounds were just so excited,” she said. “And they were excited for me. I came to school the next day, and there were three cards from some of those kids, ‘Congratulations on knowing the Pope.’”

Her joy was shared by people around the world. In the days following his election, she recalled hearing stories from Chicago, Peru, and Africa, all of which were proud to call themselves Pope Leo’s home.

Ms. Gradek said, “Everybody who has met him has felt that way.”

Ever since she attended a Catholic elementary school, Ms. Gradek’s faith has been a big part of her identity; seeing the role of Pope occupied by someone she knew has been an even more significant experience.

As for the new papacy, Ms. Gradek remains just as excited as some of her students.

“He’s got such wisdom. He thinks before he speaks, and he knows what’s troubling in the world today,” she said. “He’s just that type of person that brings people together, and makes such a connection with people—that’s why he’s going to make a great Pope.”