Described by The Guardian as a "versatile star of Hollywood’s international years whose work spanned romantic comedies, period epics and spaghetti westerns", she went on to star opposite Kirk Douglas, John Wayne, Robert Mitchum, Charlton Heston, and Anthony Quinn, be directed by André De Toth, Vittorio De Sica, Howard Hawks and Orson Welles on both sides of the Atlantic.

Outside her busy film career, Martinelli was a member of the glitterati, married to an Italian count and befriending such international celebrities as Maria Callas, Aristotle Onassis and Jackie Kennedy.

[5] That same year, she won the Silver Bear for Best Actress at the 6th Berlin International Film Festival for playing the titular role in Mario Monicelli's Donatella.

[6] From the mid-1950s through the late 1960s, Martinelli divided her time between Europe and the United States, earning major co-starring roles as the female lead in such Hollywood productions as Hatari!

From the late 1960s onward, Martinelli's output decreased as she worked in mostly European foreign-language productions, such as Manon 70 (1968); One on Top of the Other (1969); and L'amica (1969—for which she won a Silver Ribbon for Best Supporting Actress).