Starting from June 1960, he was member of Rome's communal council for his party, Democrazia Cristiana (Christian Democracy, or DC). He was a member of the corrente (political movement within DC) of Amintore Fanfani first, and Arnaldo Forlani later. He was elected mayor of Rome on 30 July 1969, being confirmed on 17 March 1972. In 1974 he formed a city council including only DC member, with indirect support by the councillors of the Italian Communist Party.
Darida was undersecretary of the Minister of the Interior in 1976-1980, and, from 1980 to 1987, Minister for the Relationship with the Parliament, Minister of the Mail, of the Public Functions, of Justice and State Participations.
During the Tangentopoli corruption scandal of the early 1990s, he was accused of bribery and shortly imprisoned. Later he was acquitted of all accusations.