On 1 July 1977 Heinz Hermann changed from FC Seefeld Zürich to Grasshopper Club Zürich, where he became Swiss league champion four times and cup champion once. At the end of the season 1984/1985 he changed to Neuchâtel Xamax, and he later played for Servette FC and FC Aarau. Between 1984 and 1988 he was awarded Player of the year five years in a row.
With 118 international matches (15 goals) between 1978 and 1991 for Switzerland he is record national player ahead of Alain Geiger and Stéphane Chapuisat. Hermann's first international match came in September 1978 with the 2:0 victory against the USA. In November 1991 he ended his international match career after a 0:1 loss to Romania.