Since the fall of 2000, Lakeside has been a member of the Wisconsin Interscholastic Athletic Association (WIAA). Prior to this, the program competed in the Wisconsin Independent Schools Athletic Association (WISAA).
Through the years, the girls have won one championship (2007) and the boys have won three championships (1992, 1999, 2023) and also brought home a team trophy with a runner-up finish (2022). The girls have made seven team appearances at the state championships and the boys have represented Lakeside ten times. Lakeside competes in Division 2 (of three divisions) with the exception of the boys in 2024 and 2025, which competed in Division 1 resulting from the WIAA's Competitive Balance Tournament Performance Factor formula.