At a very young age, he entered the Italian Communist Party (PCI) and the trade union Italian General Confederation of Labour (CGIL), which he contributed to reform after the defeat in the FIAT internal elections of 1955.

In the trade union conflict between Fausto Bertinotti (who always favoured strikes) and Sergio Cofferati (more incline to mediation), Garavini usually sided for the first policy, but also proposed intermediate solutions such as the intermittent strike or the permanent consultation.

As a member of PCI, he supported Rossana Rossanda when she formed the party-newspaper il manifesto and was later expelled from the party, but Garavini never abandoned it.

In 1995 Garavini, then a deputy for the Communist Refoundation, voted confidence to the center cabinet led by Lamberto Dini, in contrast with his party's guidelines.

Garavini wrote numerous essays on Italian politics and trade unions, such as Ripensare l'illusione.