Moira Harris was born on April 19, 1954 in Pontiac, Illinois. She attended and graduated from Illinois State University in Normal, Illinois, (also where John Malkovich attended) and met Gary Sinise during her college years. They have three children: Sophie Sinise, McCanna Anthony Sinise and Ella Sinise. She is the daughter-in-law of Robert L. Sinise. Moira converted to Roman Catholicism in 2000.