After an absence of nearly two years from the screen, Crawford staged a comeback by starring in Mildred Pierce (1945), for which she won the Academy Award for Best Actress. In 1955, she became involved with the Pepsi-Cola Company through her marriage to company president Alfred Steele. After his death in 1959, Crawford was elected to fill his vacancy on the board of directors but was forcibly retired in 1973. She continued acting in film and television regularly through the 1960s, when her performances became fewer; after the release of the British horror film Trog in 1970, Crawford retired from the screen. Following a public appearance in 1974, after which unflattering photographs were published, Crawford withdrew from public life and became more and more reclusive until her death in 1977.

Crawford married four times. Her first three marriages ended in divorce; the last ended with the death of husband Al Steele. She adopted five children, one of whom was reclaimed by his birth mother. Crawford's relationships with her two older children, Christina and Christopher, were acrimonious. Crawford disinherited the two and, after Crawford's death, Christina wrote a "tell-all" memoir, Mommie Dearest, in which she alleged a lifelong pattern of physical and emotional abuse perpetrated by Crawford.

Crawford was born Lucille Fay LeSueur in San Antonio, Texas, the third child of Tennessee-born Thomas E. LeSueur (1868–1938) and Anna Bell Johnson (1884–1958). Her older siblings were Daisy LeSueur, who died very young, and Hal LeSueur. Thomas LeSueur abandoned the family a few months before Crawford's birth. He reappeared in Abilene, Texas, in 1930 as a 62-year-old construction laborer on the George R. Davis House, built in Prairie School architecture.

Crawford's mother subsequently married Henry J. Cassin. The family lived in Lawton, Oklahoma, where Cassin ran a movie theater. Crawford was unaware that Cassin was not her birth father until her brother Hal told her. The 1910 federal census for Comanche County, Oklahoma, enumerated on April 20, showed Henry and Anna living at 910 "D" Street in Lawton. Crawford was listed as five years old, thus showing 1905 as her likely year of birth. However, the state of Texas did not require the filing of birth certificates until 1908, allowing Crawford to claim she was born in 1908.

Crawford preferred the nickname "Billie" as a child and she loved watching vaudeville acts perform on the stage of her stepfather's theater. Her ambition was to be a dancer. However, in an attempt to escape piano lessons to run and play with friends, she leapt from the front porch of her home and cut her foot deeply on a broken milk bottle. Crawford had three operations and was unable to attend elementary school for a year and a half. She eventually fully recovered and returned to dancing.

Around 1916, Crawford's family moved to Kansas City, Missouri. Cassin was first listed in the City Directory in 1917, living at 403 East Ninth Street. While still in elementary school, Crawford was placed in St. Agnes Academy, a Catholic school in Kansas City. Later, after her mother and stepfather broke up, she stayed on at St. Agnes as a work student. She then went to Rockingham Academy as a work student. While attending Rockingham she began dating and had her first serious relationship, with a trumpet player named Ray Sterling. It was Sterling who inspired her to begin challenging herself academically, and in 1922, Crawford registered at Stephens College in Columbia, Missouri. She gave her year of birth as 1906. Crawford attended Stephens for less than a year, as she recognized that she was not academically prepared for college.

Under the name Lucille LeSueur, Crawford began dancing in the choruses of traveling revues and was spotted dancing in Detroit by producer Jacob J. Shubert. Shubert put her in the chorus line for his 1924 show Innocent Eyes at the Winter Garden Theatre on Broadway in New York City. While appearing in Innocent Eyes Crawford met a saxophone player named James Welton. The two were allegedly married in 1924 and the couple lived together for several months, although this supposed marriage was never mentioned in later life by Crawford. She wanted additional work and approached Loews Theaters publicist Nils Granlund. Granlund secured a position for her with producer Harry Richmond's act and arranged for her to do a screen test which he sent to producer Harry Rapf in Hollywood. Stories have persisted that Crawford further supplemented her income by appearing in one or more stag, or soft-core pornographic, films, although this has been disputed. Rapf notified Granlund on December 24, 1924 that Metro-Goldwyn-Mayer had offered Crawford a contract at $75 a week. Granlund immediately wired LeSueur – who had returned to her mother's home in Kansas City – with the news; she borrowed $400 (which she never paid back) for travel expenses. The night after Christmas she left Kansas City and arrived in Culver City, California.

As Lucille LeSueur, her first film was Pretty Ladies in 1925, which starred ZaSu Pitts. Also in 1925 she appeared in a small role in The Only Thing and in Old Clothes opposite Jackie Coogan. MGM publicity head Pete Smith recognized her ability but felt that her name sounded fake; it also, he told studio head Louis B. Mayer, sounded like "Le Sewer". Smith organized a contest in conjunction with the fan magazine Movie Weekly to allow readers to select her new name. Initially the name "Joan Arden" was selected but, when another actress was found to have prior claim to that name, the alternate name "Crawford" became the choice. Crawford initially wanted her new first name to be pronounced "Jo-anne". She hated the name Crawford, saying it sounded like "crawfish". Her friend, actor William Haines, quipped, "They might have called you 'Cranberry' and served you every Thanksgiving with the turkey!" Crawford continued to dislike the name throughout her life but, she said, "liked the security that went with it".

Growing increasingly frustrated over the size and quality of the parts she was given, Crawford embarked on a campaign of self-promotion. As MGM screenwriter Frederica Sagor Maas recalled, "No one decided to make Joan Crawford a star. Joan Crawford became a star because Joan Crawford decided to become a star." She began attending dances in the afternoons and evenings at hotels around Hollywood, where she often won dance competitions with her performances of the Charleston and the Black Bottom. Her strategy worked, and MGM cast her in the film where she first made an impression on audiences, Edmund Goulding's Sally, Irene and Mary (1925). She played Irene, a struggling chorus girl. In the same year, Crawford worked on Lady of the Night, starring Norma Shearer. Crawford was made up and used as a double for Shearer and her face is briefly seen. Crawford coveted the roles that Shearer played but knew that Shearer's husband, producer Irving Thalberg, guaranteed Shearer first choice of roles in any MGM property. "How can I compete with Norma?" Crawford was quoted as saying. "She sleeps with the boss."

The following year, Crawford was named one of the WAMPAS Baby Stars, along with Mary Astor, Mary Brian, Dolores Costello, Dolores del Río, Janet Gaynor and Fay Wray. For the next two years, Crawford appeared in increasingly important films. In 1926, she made Paris, where she was able to show her sex appeal. She became the romantic interest for some of MGM's leading male stars, among them Ramón Novarro, William Haines, John Gilbert and Tim McCoy. Crawford appeared in The Unknown (1927), starring Lon Chaney, Sr. who played a carnival knife thrower with no arms. Crawford played his skimpily clad young carnival assistant whom he hopes to marry. She stated that she learned more about acting from watching Chaney work than from anything else in her career. "It was then", she said, "I became aware for the first time of the difference between standing in front of a camera, and acting."