Welch first won attention for her role in Fantastic Voyage (1966), after which she won a contract with 20th Century Fox. They lent her contract to the British studio Hammer Film Productions, for whom she made One Million Years B.C. (1966). Although Welch had only three lines of dialogue in the film, images of her in the doe-skin bikini became bestselling posters that turned her into an international sex symbol. 

         Through her portrayal of strong female characters, which helped in her breaking the mold of the traditional sex symbol, Welch developed a unique film persona that made her an icon of the 1960s and 1970s. Her rise to stardom in the mid-1960s was partly credited with ending Hollywood's vigorous promotion of the blonde bombshell. She won a Golden Globe Award for Best Motion Picture Actress in a Musical or Comedy in 1974 for her performance in The Three Musketeers. She was also nominated for a Golden Globe Award for Best Actress in Television Film for her performance in the film Right to Die (1987). In 1995, Welch was chosen by Empire magazine as one of the "100 Sexiest Stars in Film History". Playboy ranked Welch No. 3 on their "100 Sexiest Stars of the Twentieth Century" list.

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