Italian anarchist and agitator, a leading advocate of “propaganda of the deed,” the doctrine urged largely by Italian anarchists that revolutionary ideas could best be spread by armed insurrection.

Malatesta became politically active while still in his teens, joining the First International (International, First) in 1871. A dynamic speaker and propagandist, he soon became a leader in the anarchist movement and helped organize anarchist revolutionary groups in Romania, Italy, Spain, and elsewhere in Europe, in Egypt, and in North and South America, including Argentina. Imprisoned for a total of about 12 years during his long career, he was sentenced to death three times and spent some 35 years in exile. Though often associated with the Russian anarchist Peter Kropotkin (Kropotkin, Peter Alekseyevich), Malatesta laid more emphasis on the organization of revolutionaries and workers as a means of achieving anarchist political goals. Accordingly, he helped organize workers' congresses in France, Belgium, and Switzerland at which he urged armed revolt, and subsequently he was banished from each of those countries.

In 1899 he visited the United States, lecturing and editing an anarchist journal. After 1900 he lived more or less quietly in London for many years, taking time out to agitate for revolution in Italy in 1913–14. He returned permanently to Italy after an amnesty in 1919, engaging in political activity until the Fascists' rise to power in 1922.