She is the daughter of actress Meryl Streep and sculptor Don Gummer. Gummer began her acting career as a child, under the name Jane Gray, when she appeared with her mother in the 1993 film House of the Spirits. She graduated from Vassar College before making her stage debut in 2008.
Gummer received a Theatre World Award for her Broadway debut in the 2011 revival of the play Arcadia. Her television work includes recurring roles on the HBO series The Newsroom (2013–14), and the FX series American Horror Story: Freak Show (2014–15), as well as regular roles on the CBS series Extant (2014–15).