Between 1949 and 1957 Bannwart played 263 games for Basel and scored 64 goals; 171 games were in the
Nationalliga A, 20 in the
Swiss Cup and 72 were
friendly games. He scored 44 goals in the domestic league, 6 in the Cup and the other 14 were scored in the friendliames. His first game in the domestic league was on 20 November 1949 in a home game in the
Stadion Schützenmatte against
FC Bern. He scored twice as Basel won 3–1. The biggest success in his football career was as Basel won the championship title in
the 1952–53 season. During this season Bannwart played 26 league games and scored 9 goals for the club. Joint with
Walter Bielser and
René Bader, Bannwart was the team's second most successful league scorer that season, behind
Josef Hügi with 32. ==International football==