Petroni was a founder of and/or leading participant in numerous Trotskyist groups in Latin America, Europe and the United States, he has extensive organizing skills and experience in working class struggles.

Petroni was a member and leader of the Argentine Partido Socialista de los Trabajadores (PST) from 1973 to 1976, and during the beginning of the military dictatorship was part of its underground continuation.

[5][6] In 2000, he wrote and managed Proposition F, considered a historical reparation Act for African American City residents, which obtained more than 45% of the vote.

As a result of his trade union and political work in Argentina, he was the target of three assassination attempts during 1974 and 1975 by death squads organized by the Argentine Anticommunist Alliance (Triple A).

Petroni has introduced into the federal court proceedings motions asking Judge Oyarbide to order the arrest of more than a dozen members, mostly union officials from Mar de Plata, Argentina, of the right wing terrorist organization CNU (which became part of the Triple A) and to question in court the knowledge of their crimes by their associate and present day General Secretary of the CGT, Hugo Moyano, who is now also vice president of the Peronist Justicialist Party.

[1][10][11] The 2010 documentary film Parapolicial Negro: Apuntes para una prehistoria de la Triple A features interviews with Petroni about the assassination attempts.