Dolores Costello was born in Pittsburgh, the daughter of actors Maurice and Mae Costello, of Irish and German descent, respectively. She and her younger sister, Helene, made their first film appearances in the years 1909–1915 as child actresses for the Vitagraph Film Company. They played supporting roles in several films starring their father, who was a popular matinee idol at the time. Dolores Costello's earliest listed credit on the IMDb is in the role of a fairy in a 1909 adaptation of Shakespeare's A Midsummer Night's Dream.
The two sisters appeared on Broadway together as chorines and their success resulted in contracts with Warner Brothers Studios. In 1926, following small parts in feature films, she starred opposite John Barrymore in The Sea Beast, a loose adaptation of Herman Melville's Moby-Dick. Warner Bros. soon began starring her in her own vehicles. Meanwhile, she and Barrymore became romantically involved and married in 1928.
Within a few years of achieving stardom, the delicately beautiful blonde-haired actress had become a successful and highly regarded film personality in her own right, and as a young adult her career developed to the degree that in 1926, she was named a WAMPAS Baby Star, and had acquired the nickname "The Goddess of the Silver Screen".
Warners alternated Costello between films with contemporary settings and elaborate costume dramas. In 1927, she was re-teamed with John Barrymore in When a Man Loves, an adaptation of Manon Lescaut. In 1928, she co-starred with George O'Brien in Noah's Ark, a part-talkie epic directed by Michael Curtiz.
Costello spoke with a lisp (something that her granddaughter, Drew Barrymore, seemingly inherited), and found it difficult to make the transition to talking pictures, but after two years of voice coaching she was comfortable speaking before a microphone. One of her early sound film appearances was with her sister Helene in Warner Bros.'s all-star extravaganza, The Show of Shows (1929). Her acting career became less a priority for her following the birth of her first child, Dolores Ethel Mae "DeeDee" Barrymore (born April 8, 1930) and she retired from the screen in 1931 to devote time to her family. She would have another child (John Drew Barrymore), but the marriage proved too difficult due to her husband's increasing alcoholism, and they divorced in 1935.
She resumed her career a year later and achieved some successes, most notably in Little Lord Fauntleroy (1936), and The Magnificent Ambersons (1942). She retired permanently from acting following her appearance in This is the Army (1943), again under the direction of Michael Curtiz.
In 1939, she married Dr. John Vruwink, an obstetrician, but they divorced in 1950. Costello spent the remaining years of her life in semi-seclusion, managing an avocado farm. Her film career was largely ruined by the destructive effects of early film makeup, which ravaged her complexion too severely to camouflage. Her final film was This Is the Army (1943). In the 1970s her house was inundated in a flash flood which destroyed a lot of her property and memorabilia from her movie career and life with John Barrymore.
Shortly before her death, she agreed to be interviewed for the documentary series Hollywood discussing her film career. She died from emphysema in Fallbrook, California, in 1979, and was interred in Calvary Cemetery, East Los Angeles. Her interview scenes were broadcast posthumously in 1980.
Dolores Costello has a star on the Hollywood Walk of Fame for her contributions to Motion Pictures, at 1645 Vine Street.