Moira Harris was born in Pontiac, Illinois, to the well-respected Harris family. She attended and graduated from Illinois State University in Normal, Illinois, (also where John Malkovich attended) and met Gary Sinise during her college years.



Although she acted in the first film her husband Gary Sinise directed, Miles from Home (1988), her small role was left on the cutting-room floor. An ensemble member of the Steppenwolf Theatre Company. She was awarded the Chicago Emmy Award for her performance in "Murder in Green Meadow". She was nominated for a 1987 Joseph Jefferson Award for Actress in a Principal Role in a Play for "Bang" at the Steppenwolf Theatre Company in Chicago, Illinois.