Monroe, Marilyn (1926-1962), American motion-picture actor, who became the most famous international sex symbol of the 20th century. Born Norma Jean Mortenson in Los Angeles, the daughter of an emotionally unstable mother, she spent a troubled childhood in foster homes and orphanages and at the age of 16 entered into an ill-fated marriage. In 1944, while working in a defense plant, she was noticed by a United States Army photographer who induced her to pose for posters for the troops. Instantly popular as a model, Monroe soon found other assignments and registered with a modeling agency, which sent her to charm school and put her on a number of magazine covers. She was signed by the 20th Century-Fox film studio in 1946 but had only two small film roles before she was dropped by the studio. In 1948 she was briefly under contract to Columbia Pictures, and although she was soon out of work again, this stint yielded appearances in a low-budget musical, Ladies of the Chorus (1949), and in the film Love Happy (1949), in which she had a bit part with the Marx Brothers.
In 1950 20th Century-Fox signed Monroe to another contract, and over the next few years she appeared in a series of small parts in films that began to gain her increased attention. Notable among these were Asphalt Jungle (1950) and All About Eve (1950). Monroe also appeared in Love Nest (1951), Clash By Night (1952), and Monkey Business (1952; with Cary Grant and Ginger Rogers) and had her first lead role in Don't Bother to Knock (1952), as a psychotic babysitter. By 1953 she was appearing as a star in such films as Niagara, How to Marry a Millionaire, and Gentlemen Prefer Blondes (as Lorelei Lee).
The sex-symbol phase of her career followed, in which her wide-eyed charm, physical voluptuousness, and natural sex appeal made her internationally renowned and her looks and mannerisms were widely imitated. Famous films of this period, during which she was 20th Century-Fox's leading box-office attraction, include River of No Return (1954), There's No Business Like Show Business (1954), and The Seven-Year Itch (1955; directed by Billy Wilder). In 1954 Monroe married baseball player Joe DiMaggio, but they were divorced a year later. In 1955 she rebelled against her long succession of stereotyped roles, announced that she was forming her own production company, and went to New York City to attend classes at the Actors Studio. She was, however, subsequently induced to remain at 20th Century-Fox with a contract that offered her more creative control. In 1956 she married playwright Arthur Miller, whom she had met in New York City and who later scripted her last film. She made The Prince and the Showgirl--a critical and commercial failure--with Laurence Olivier in 1957, gave a noted performance as the singer Sugar Kane in Some Like It Hot (1959; directed by Wilder), and appeared with Yves Montand in Let's Make Love (1960).
During this period, under the constant care of a psychiatrist, beset by depression and illness, and prone to mix prescription drugs with alcohol, Monroe was becoming increasingly unreliable. Her final film was The Misfits (1961), written for her by Miller and directed by John Huston. A week after the film opened, she divorced Miller. In the summer of 1962 she was fired from the set of her latest picture, and a month later she was found dead in her home, the apparent victim of a barbiturate overdose (although suicide was not ruled out).
Monroe's autobiography, My Story, appeared in 1974, and many celebrity biographies and collections of still photographs of her have also been published. In addition, her life has been the subject of several documentaries and fictionalized film treatments.