Farrow was born in Los Angeles, California, the third child and eldest daughter of Australian film director John Farrow (John Villiers Farrow) and Irish actress Maureen O'Sullivan. Both Farrow's mother and father were from Catholic families. She is one of seven children, with older brothers Michael Damien (1939-1958), Patrick (1942-2009), younger brother John Charles (born 1946); and younger sisters Prudence and actresses Stephanie and Tisa. Her eldest brother, Michael Farrow, died in a plane crash in 1958, at age 19; Patrick, a sculptor, committed suicide in 2009; and John Charles was in 2013 sentenced to 25 years in prison for child molestation, for sexually abusing two boys over a period of eight years.

Farrow screen-tested for the role of Liesl von Trapp in The Sound of Music, but did not get the part. The footage has been preserved, and appears on the fortieth Anniversary Edition DVD of The Sound of Music. Farrow began her acting career by appearing in supporting roles in several 1960s films, making her first credited appearance in Guns at Batasi (1964). The same year, she achieved stardom on the popular primetime soap opera Peyton Place as naive, waif-like Allison MacKenzie. Farrow left the series in 1966 at the urging of Frank Sinatra whom she married on July 19, 1966. Before her acting career, Farrow worked as a fashion model for many years.  Farrow's first leading film role was in Rosemary's Baby (1968), which was a critical and commercial success at the time and continues to be widely regarded as a classic of the horror genre. Her performance garnered numerous awards, including the Golden Globe Award for New Star of the Year - Actress, and established her as a leading actress. Film critic and author Stephen Farber described her performance as having an "electrifying impact... one of the rare instances of actor and character achieving a miraculous, almost mythical match". Film critic Roger Ebert called the film "brilliant", and noted, "A great deal of the credit for this achievement must go to Mia Farrow, as Rosemary".  Following Rosemary's Baby, Farrow was to be cast as Mattie in True Grit and was keen on the role. However, prior to filming she made Secret Ceremony in England with Elizabeth Taylor and Robert Mitchum. While filming, Mitchum told her about True Grit director Henry Hathaway having a reputation for being rude to actresses. Farrow asked producer Hal Wallis to replace Hathaway. Wallis refused; Farrow then quit the role, which was then given to Kim Darby. Secret Ceremony divided critics, but has gone on to develop a devoted following. Farrow's other late 1960s films include John and Mary, opposite Dustin Hoffman.  In the 1970s, Farrow performed in several classical plays in London including Mary Rose, The Three Sisters, and Ivanov. She became the first American actress to join the Royal Shakespeare Company. During this time she appeared in several films, including the thriller See No Evil (1971), French director Claude Chabrol's Docteur Popaul (1972) and The Great Gatsby (1974), in which Farrow played Daisy Buchanan. She appeared in director Robert Altman's cult classic A Wedding (1978). In 1977, she played the title role in The Haunting of Julia. Farrow appeared in several made-for-television films in the 1970s, most notably portraying the title role in a musical version of Peter Pan (1976). In 1979, she appeared on Broadway opposite Anthony Perkins in the play Romantic Comedy by Bernard Slade.

What did she work on after Peyton Place
Farrow's first leading film role was in Rosemary's Baby (1968),