In 1897, Labriola joined Italian Socialist Party (PSI) and fought in the Greco-Turkish War in Crete.

[3] He returned to Italy in 1900, and in 1902 published a weekly called Avanguardia Socialista which became the centre of activity for Italian revolutionary syndicalism.

[4] He later withdrew his support for revolution, and adopted Marxist Reformism, becoming a member of the Italian Parliament as an independent.

Favourable to Italy's participation in World War I, Labriola also served as Minister of Labor in the last of Giovanni Giolitti's cabinets (1920).

As it was confirmed by the former President of the Grand Orient of Italy, he was one of the eight father constituents belonging to the main Italian Masonic organization.