Born in the Italian town of La Spezia in Liguria, he was originally interested in electronics, studying it in Naples for a decade before shifting his interest to acting. At 18, he joined the Academy of Dramatic Art D'Amico in Rome, and made his stage debut as Puck in a 1961 production of Shakespeare's "A Midsummer Night's Dream." Giannini quickly amassed a wealth of theatrical experience, including a turn as Romeo in a production of "Romeo and Juliet" for Franco Zefferelli in 1964. His screen debut came with "Fango di Metropoli" in 1965, as did his first television appearance as Charles Dickens' hero "David Copperfield" for RAI. The following year, Giannini starred in the play "Two and Two are No Longer Four" by Swiss-born writer and director Lina Wertmuller. The two quickly developed a rapport, which led to Wertmuller casting him in her film "Rita the Mosquito" (1967), which would precede a long and fruitful collaboration between the actor and the director, both as co-muses and production partners.Giannini's U.S. film debut came a year later in the World War II action-drama "Anzio" (1968), which was followed by "The Secret of Santa Vittoria" (1969), which cast him as an Italian villager aiding Anthony Quinn in hiding his town's precious cache of wine from the Nazis. But by the early 1970s, he was working almost exclusively in Italy with Wertmuller, who gave Giannini some of his greatest showcases as a performer. Sensing his capacity for finding both the humor and tragedy in every situation, Wertmuller cast him as decidedly average men who must rise above their mundane circumstances to extract themselves from unusual and even dire predicaments. In "The Seduction of Mimi" (1973), his dense, stubborn quarry worker is embroiled in a variety of sticky situations, including a show-stopping scene in which he attempts to get revenge on a local Fascist by impregnating his morbidly obese wife. "Love and Anarchy" (1973) earned him top acting honors at the Cannes Film Festival as an naïve Italian peasant whose plans to assassinate Mussolini are undone after he falls in love with an apolitical prostitute. Their first big box office success came with "Swept Away " (1974), a politically imbued sex comedy about a Marxist deckhand (Giannini) and a spoiled bourgeoisie (Mariangelo Melato) who become unlikely lovers after they are stranded on a desert island."Seven Beauties" (1975) thrust Giannini into the international spotlight when he received an Oscar nomination for his performance as a two-bit hood who must seduce a monstrous Nazi officer (Shirley Stoler) in order to survive his internment in a concentration camp. The pair would work together on several subsequent films, including her first American-made film, "A Night Full of Rain" (1977), and "Blood Feud" (1978), but Giannini soon found himself in demand with other directors, including Rainer Werner Fassbinder, who cast him as a Jewish musician arrested by the Nazis in "Lili Marleen" (1981). He also began a long and lucrative career dubbing the voices of numerous top American actors for the Italian market, including Jack Nicholson and Al Pacino. Giannini's dubbing for Nicholson in "The Shining" (1980) reportedly earned him a fan letter from the film's director, Stanley Kubrick, himself.In the 1980s, Giannini began making inroads into international productions, especially in America, where his fluent English helped him land numerous roles in features and television. His efforts in this market were frequently hit-or-miss - for every "American Dreamer" (1984) or "Fever Pitch" (1985) for Richard Brooks, there was something like "Sins" (CBS, 1986), a sudsy miniseries with Joan Collins - but occasionally, he landed a quality project like Francis Ford Coppola's segment of "New York Stories" (1989), which cast him as the divorced father of a young girl on a fairy tale adventure. Giannini also made his directorial debut during this period with "Ternosecco" (1986), which he also wrote.In 1995, Giannini received his widest exposure to American audiences as the proud patriarch of a Sacramento wine vineyard in Alfonso Arau's "A Walk in the Clouds." Though dismissed by many as a sudsy remake of the 1942 Italian film "Quattro Passi Fra Le Nuove," its romantic tone and sweeping cinematography won the hearts of many movieg rs. Giannini soon became a semi-regular face in American features, frequently as cagey, well-lived older men with a degree of insight to share with the film's leads. He was the corrupt Emperor Shaddam IV in the miniseries adaptation of "Frank Herbert's Dune" (Sci Fi Channel, 2000), and an Italian detective on the trail of Anthony Hopkins in "Hannibal" (2001). The HBO production "My House in Umbria" (2003) found him as another Italian cop attempting to solve a train bombing, while "Man on Fire" (2004) saw him sharing the screen with Denzel Washington and Dakota Fanning. Giannini also remained remarkably active in Italian productions during this period, with up to five features to his name in a single year.In 2006, he joined the revamped James Bond franchise with a major supporting role in "Casino Royale." His character, Rene Mathis, was a suave French agent who appears to aid Bond throughout his adventure, only to serve as his undoing by revealing key information to his adversary, Le Chiffre (Mads Mikkelsen). Giannini returned as Mathis in the sequel, "Quantum of Solace" (2008), in which he is cleared of any wrongdoing, only to be killed by corrupt police officials after aiding Bond.