A video from the ABC7 Chicago channel shows the pontiff greeting the students dressed as cardinals.
"I feel a little weird because I'm wearing exactly the same thing as him," student Auggie Wilk tells the station.
The fourth-grader was elected "Pope Augustine" in the mini-conclave and entered St Peter's Square wearing a white cassock and pileolus.
The pupils were accompanied in the audience by the current Archbishop of Chicago, Cardinal Blaise Cupich, who travelled to Rome this week to celebrate his 50th anniversary as a priest.
After meeting the Pope, fourth-grader Wilk reports in an interview that he was allowed to swap his crown cap with that of Pope Leo XIV for a short time.
One pupil - also dressed as a cardinal - said: "I was able to shake his hand, along with many others. It was very exciting."
"This is a story for my children"
The pupils of the Catholic school "Our Lady of Mount Carmel Academy" re-enacted the conclave as part of a class project in May.
The aim was to teach the pupils about the meaning and process of the papal election in a fun way.
Cardinal Cupich also learnt about this during his stay in Rome for the papal election. On his return, he visited the school and was shown the "mini-conclave" a second time.
The video of the re-enacted papal election went viral and was picked up by the media worldwide.
What began in May in Chicago, the home of the reigning Pope, ended with an excursion to Rome.
When asked by the reporter from ABC7 Chicago whether the students could ever have imagined that this class project would lead to them meeting the Pope, one student replied: "No, I thought it was a one-off."
And, "This is a story for my kids, I'm going to tell everyone."