Tognoli was born at Milan and joined the Italian Socialist Party (Partito Socialista Italiano, or PSI) in 1958.

In 1984–1987 he was also elected to the European Parliament; in the latter year, he was appointed Minister of Problems of Urban Areas in the cabinets of Giovanni Goria and Ciriaco De Mita.

In 1992, he was involved in the Tangentopoli scandal together with his party colleague Paolo Pillitteri (who had been his successor as mayor of Milan).

Tognoli subsequently abandoned political activity and in 1995 obtained a position in Mediobanca thanks to the intercession of Enrico Cuccia.

[1] Tognoli died in Milan on 5 March 2021, at the age of 82, from complications from COVID-19 during the COVID-19 pandemic in Italy.