Mike attended St. Rita of Cascia High School in Chicago where he played football and baseball. He was the team captain for both teams. In football, he led the Mustangs to three conference championships and had a career record of 35–8. As a senior in 2004, Kafka completed 75 of 129 passes. In the season-opener against Homewood-Flossmoor High School, Kafka went up against H-F’s quarterback Freddie Barnes and won the game, 52–28. Against Mt. Carmel High School, he ran for 164 yards and passed for 126 yards. Kafka passed for 1,004 yards and 10 touchdowns in 2004. He ran for 806 yards with a 5.6 yards per carry average, and five touchdowns on 144 carries. His career stats at St. Rita were 1,816 total offensive yards and 16 touchdowns.
Mike made the school’s Silver Honor Roll all four years of high school and was an Academic All-State. He was an All-area selection by Tom Lemming’s Prep Football Report and was an honorable mention all-state selection. SuperPrep named him All-Midwest Region and Rivals.com placed him on the Top 25 dual-threat quarterbacks list. SuperPrep ranked him 25th among players from Illinois at all positions and 50th nationally among quarterbacks. He was ranked 20th in Illinois by Rivals.com and 25th nationally among dual-threat quarterbacks. Kafka was named Team Offensive MVP and Catholic Metro Blue Offensive MVP. He was an honorable mention all-area honoree by Chicago Sun-Times and Daily Southtown.
