斯洛伐克共产党
Schuster was born in Košice. From 1964 to 1990, he was a member of the Communist Party of Slovakia. Before becoming president, he was Mayor (Slovak: "primátor") of Košice in 1983–1986 and 1994–1999 respectively. He was also the last Communist president of the Slovak National Council (1989–1990), Ambassador of Czechoslovakia to Canada (1990–1992) and a leader of the Party of Civic Understanding ("SOP – Strana občianskeho porozumenia", 1998–1999).