Brosch is product of Jefferson County, MO where he started playing lacrosse with the Fox Warriors Lacrosse Club helping them win a Division II MO State Title in 2008. Brosch attended NCAA Div. III Whittier College before transferring to Missouri Baptist University. At MBU Brosch was a 3 x MCLA Div. II All-American Face-off Specialist finishing his college career with a combined 84% win percentage. He also holds the team record for most points in a season with 62 (2013). In 2019 Brosch was named to the MCLA Div. II All-Decade Team. Most recently, Brosch played for the St. Louis Centurions winning two IBLA RBLLMO Championships (2018, 2019) and one BLL Championship (2017).