Famous for her Ruby Oliver series of young adult novels, as well as for her acclaimed standalone works We Were Liars (2014) and The Disreputable History of Frankie Landau-Banks (2008), Lockhart is also notable for her picture books for younger children, which include Princessland (2014) and Skunkdog (2008).
After earning her undergraduate degree from Vassar College, she received a PhD in English literature from Columbia University.
In addition to her works for young readers, she penned books for adults titled Mister Posterior and the Genius Child (a novel) and Tongue First: Adventures in Physical Culture (an essay collection).
Born Emily Jenkins, she spent her early years in Cambridge, Massachusetts and Seattle, Washington and later settled in her birth city of New York, New York. She and her father, Len, co-wrote a children's book titled The Secret Life of Billie's Uncle Myron.
She and fellow young adult author Lauren Myracle collaborated on a 2008 work titled How To Be Bad.