St. John Cantius Church has witnessed a number of famous visitors from Poland within its walls. In March 1989, the parish hosted a visit by Tadeusz Mazowiecki, Prime Minister of the newly-democratic Poland, while in 1998, Józef Glemp, the Cardinal Primate of Poland came to celebrate a Mass of Thanksgiving and bless the church's new copper cupola. In June 2017, Polish MP Malgorzata Gosiewska visited Saint John Cantius as well as a number of other Polish Churches during an official visit to Chicago.