An American by birth, Andrea Harris trained at the Bristol Old Vic Theatre School and the American Conservatory Theatre. According to The New York Times, her maternal grandparents "the late Mamie Phipps Clark and the late Kenneth B. Clark, psychologists and educators whose research with black children was used by the N.A.A.C.P. in arguments to the Supreme Court that led in 1954 to the landmark decision in Brown v. the Board of Education" (24 September 2010). Harris understudied Penny Downie as Gertrude in David Tennant's Hamlet, Nina Sosanya as Rosaline in Love's Labour's Lost and Hippolyta in A Midsummer Night's Dream in 2008 at the RSC. Prior to working with the RSC, Harris had also appeared in A Midsummer Night's Dream and Pericles at the Oregon Shakespeare Festival (no further information known about these productions).