Born Mary Willa Gummer on August 08, 1983 to sculptor Don Gummer and actress Meryl Streep. She grew up in rural Connecticut with an older brother and two younger sisters. Through her mother’s profession, Mamie made her uncredited screen debut with 20 months of age as the baby of Meryl and Jack Nicholson in Mike Nichols’ “Heartburn”. Gummer graduated from Northwestern University and then studied at the British Academy of Dramatic Arts. She subsequently made her stage debut in the Roundabout Theater Production of Noah Haidle’s “Mr. Marmalade” (2005), directed by Michael Greif. In 2006, she starred with Kate Burton and Tony Goldwyn in Theresa Rebeck’s “The Water’s Edge”, directed by Will Frears at NYC’s Second Stage Theatre. For her performance, Mamie won a Theatre World Award for “Mr. Marmalade” and received a nomination for the Lucille Lortel Award for “The Water’s Edge”.

Mamie Gummer made her motion picture debut with a minor role in Lasse Hallström’s “The Hoax”, opposite Richard Gere and had her breakthrough role in the 2007 release “Evening”, directed by Lajos Koltai and co-starring Claire Danes, Toni Collette, the late Natasha Richardson, Glenn Close and Meryl Streep. Mamie was next seen in Kimberly Peirce’s “Stop Loss” and on tv in HBO’s epic mini-series “John Adams”, starring Paul Giamatti & Laura Linney. Alongside Linney, Mamie made her Broadway debut with an acclaimed performance in a revival of “Les Liaisons Dangereuses”. In 2009, she won rave reviews for performance as Sonya in the Classic Stage Company’s production of “Uncle Vanya”, winning her a second Lucille Lortel Award nomination. Mamie completed Jodie Markell’s ensemble drama “The Loss of a Teardrop Diamond”, based on the novel by Tennessee Williams as well as Ang Lee’s “Taking Woodstock” in 2009. Mamie landed her first regular role in a television series in 2010's "Off the Map", playing a young doctor who serves in a djungle hospital. The series was not renewed by ABC after its first season. Gummer also has a recurring role on the acclaimed "The Good Wife", having appeared three times as lawyer Nancy Crozier. In 2011, she had a starring role in the critically panned "The Ward", directed by John Carpenter and the little-seen "Twelve Thirty".

Mamie Gummer is married to actor Benjamin Walker.