István Schillerwein started his racing career in 1948 with the Hungarian War of Independence Association. In 1949 he joined the newly formed squad, Budapesti Honvéd. Schillerwein won his first senior national championship title at age 17, with the Honvéd team pursuit. He followed this with another 10 senior championships in other track disciplines. Schillerwein competed at the 1952 Helsinki Olympics on both road and track, placing fifth in the tandem sprint. He also won a gold medal in team pursuit at the 1954 Universiade. Schillerwein later became a coach with FTC in 1958, and in the 1970s, became coach of the Hungarian national team.