Named for Shirley Temple, actress, dancer, singer, author, spiritualist, activist Shirley MacLaine was born in Arlington, Virginia to a drama teacher mother and a professor father (her brother is actor Warren Beatty). Because she had weak ankles, her mother enrolled her in ballet classes. She excelled at ballet and won many of the male roles because of her height, but ultimately gave it up because, among other reasons, she found it too limiting. Acting in high school productions, she went to New York one summer to try her hand at Broadway and, returning after graduation, ended up an understudy performing in The Pajama Game when the actress broke her ankle. She was noticed by a film producer, signed to Paramount Pictures, and the rest is history.

MacLaine made her film debut in Alfred Hitchcock's 1955 film The Trouble with Harry, and went on to star in numerous comedies and dramas alongside Rat Packers Dean Martin, Frank Sinatra, Sammy Davis, Jr. (Some Came Running, Oceans Eleven, Can-Can) and others. Her performances won her Academy Award and Golden Globe nominations (alongside Jack Lemmon in Billy Wilder's The Apartment; Audrey Hepburn in Lillian Hellman's The Children's Hour; Ann Bancroft in The Turning Point; and Peter Sellers in Being There). Meanwhile, she took her one-woman show A Gypsy in My Soul to Broadway and harnessed her celebrity to campaign in two successive Democratic presidential campaigns: Robert Kennedy in 1968 and George McGovern in 1972. But it wasn't until 1983 that she cemented her reputation professionally and personally, winning her Academy Award for James L. Brooks' Terms of Endearment, and publishing her candid autobiography Out on a Limb, describing her interests and experiences in spirituality, metaphysics, and reincarnation.

In the late 1980s through the '90s, MacLaine turned in numerous iconic performances in films such as Madame Sousatzka, Postcards from the Edge, Steel Magnolias, and Guarding Tess. In 2012, she was awarded an AFI Lifetime Achievement Award.

MacLaine describes her much-anticipated role as Downton Abbey's Martha Levinson, opposite Dame Maggie Smith's Violet, as nuanced, "The gunfight at the OK Corral does not happen between Maggie and me. We do a little sparring, we have our moments, but it's more sophisticated than that. Martha is not just a crass, cranky American coming in there. She's very smart, and to a large extent sensitive as to what's going on with all her daughters' children. And Maggie's character is so well established, but you have to look beyond what is her expected reaction to Martha. The Dowager Countess is a human being who has complications and a past of some pain that Martha understands – and to some extent addresses herself to." And of filming at Highclere Castle, MacLaine describes a "once-in-a-lifetime experience, to shoot in such a hallowed place. I enjoyed very, very much that castle and the grounds and the past and the hauntings and the energy."