Poli was one of the best known and most active characters of Italian cinema; in his thirty-five-year career, he appeared in over 200 films.

He started from a young age by treading the stages and reciting in Roman dialect.

In 1951 he had a small part in the film Toto and the King of Rome directed by Mario Monicelli.

He played characters such as bartenderd, a docker, a prisoner in the films of the Monnezza to those of Bernardo Bertolucci.

Notable films Poli appears in include The Overcoat (1952) by Alberto Lattuada; Toto in Color (1952) by Steno; Termini Station (1953) by Vittorio De Sica; Beat the Devil by John Huston; Nights of Cabiria (1956) by Federico Fellini; Poor, But Handsome (1956) by Dino Risi; You're on Your Own (1959) by Mauro Bolognini; Totò, Peppino e... la dolce vita (1961) by Sergio Corbucci; The Betrayer (1961) by Roberto Rossellini.