Became widely popular with Luchino Visconti's theater company, performing in important plays such as Tennessee Williams' "Un tram che si chiama desiderio" (A Streetcar Named Desire) or William Shakespeare's "Rosalinda".
Born to a father from a wealthy family of German origins and a mother from Pisa.
Father of actress Paola Gassman, doctor Vittoria Gassman, actor Alessandro Gassman and Jacopo Gassman, grandfather of assistant director Tommaso Pagliai.
Founded and ran for years one of the most select acting schools.
From 1953 until 1960 he was the partner of actress Anna Maria Ferrero.
From 1961 until 1963 he was the partner of actress Annette Vadim.
From 1964 until 1968 he was the partner of actress Juliette Mayniel. They have a son, actor Alessandro Gassman.
In his public appearances, he often criticized moderated cultural positions and gained some enemies in the world of art for his frank judgments.
Shares his birthday with actress Yvonne De Carlo.
Studied acting at the Accademia Nazionale d'Arte Drammatica in Rome.
The standard joke on him was that he had such an interesting, flexible voice (and such an outstanding acting ability) that he could have made everything he read entertaining and intense. In mid-90s, a satirical show on Italy national TV gave him a 2 minutes space (named "Gassman Legge", literally "Gassman Reads") where he just "acted" few lines from banal, utterly non-poetic texts, e.g. the Yellow Pages, a blood test report, a telephone bill, the classifieds page in a local newspaper and so on. The segment was a success.