In 1969, together with Alberto Franceschini and other former Communist militants, Gallinari decided to pursue armed terrorism. After a short period as a member of the Superclan, he became a member of the Red Brigades, initially as an external collaborator, then as a full clandestine member. In 1974 he took part in the kidnapping of judge Mario Sossi and was later arrested in Turin, together with Alfred Bonavita. In 1976 he escaped from the prison of Treviso. He then belonged to the Roman "column" of the BR, and had a relevant role in the kidnapping of Aldo Moro, a Christian Democratic former prime minister of Italy. Gallinari was one of the killers who ambushed the politician's car in Via Fani in Rome, assassinating three of the policemen who were part of Moro's armed escort. After Moro's kidnapping, Gallinari became a member of the executive committee of the BR. Moro was subsequently killed in obscure circumstances the following May.
Arrest
Gallinari was arrested on 24 September 1979 while changing number plates on cars which would be used in a Red Brigade action. He was shot twice by the Italian police before he was arrested and underwent a five-hour emergency operation. Initially, he was convicted of killing Moro. However, later it was learned that not Gallinari but another Red Brigades militant, Germano Maccari, had killed Moro. According to the official trial reconstructions, Gallinari was present in the BR hideout in Rome where Moro was detained for 55 days, along with Moretti, Anna Laura Braghetti and Germano Maccari. During his detainment, Gallinari was one of the few BR terrorists who did not collaborate with the Italian justice. Instead, he continued to have contacts with the organization's free members and indirectly participated in their political debates.
Semi-liberty regime
In October 1988, after most of the organization's members had been arrested, he co-signed a document with several other arrested Red Brigades terrorists confirming their belief in their creed. Due to health concerns, Gallinari was allowed to spend certain periods of time outside the prison walls. In March 2006, he published an autobiographical book, providing his own version of the Red Brigades' deeds.