St. John Brebeuf Church has a large and active congregation, as well as the only Catholic school in Niles. In addition to its traditional base of Italian, Irish and German American Catholics, the parish serves a large number of Polish congregants, many of whom are first generation. The church offers two well-attended Polish-language Masses each weekend. Filipino, Hispanic and other parishioners also contribute to the congregation's diversity. 

The Parish Ministry Center, with distinct architecture and cleverly placed windows to let in natural light, was founded Oct. 1, 2004 and later named the May Parish Ministry Center to honor the pastor, Fr. Tom May. It provides a place for parishioners, school children, Scouting and other groups to gather, and a setting for lectures, performances, celebrations,  fundraisers and school plays.

The parish has more than 40 ministries, including the St. Vincent DePaul Society, Catholic Women's Club, Holy Name Society, St. Queen Jadwiga, Knights of Columbus, and Girl and Boy Scouts.

A Perpetual Adoration chapel, which is open 24 hours a day for quiet prayer and devotion, is located inside the ministry center.

Mass times are: Sat 7:30 am and 5 pm English, 6 pm Polish.  Sun 7:30am, 9am, 10:45am English and 12:30pm Polish. Mon-Fri 6:30 and 8:45am English.