Roncalli has a rich basketball tradition that has had teams go to the WIAA state tournament eight times since the 2004-05 basketball season. Most years, Roncalli will find itself ranked in the top 10 teams in the state for their respective division. The Roncalli boys basketball team consists of three levels of teams (JV2, JV and varsity) and competes in the Eastern Wisconsin Conference. The varsity team won the state championship in 2021.
The Roncalli boys basketball experience starts for boys when they are in third grade where they learn the fundamentals of the game and begin to learn the basic concepts of Roncalli's offensive and defensive systems. The majority of the youth teams consist of players that go to Roncalli Elementary School or Roncalli Middle School, however Coach Josh Erickson and the coaching staff welcome anyone who has an interest in playing the sport. The Junior Jets teams start playing in third grade and play through eighth grade where the players then have the opportunity to play at the high school level if they choose to play.
Nathan Kaderabek serves as the assistant coach for the varsity team.
The JV team is coached by Joe Pozorski and JV2 is coached by Cody Krueger. Jeff Chalupny works with both teams.