Born in Helena, Montana, Kerry Cahill grew up in small rural towns of Montana, Oregon and Texas. Cahill studied Drama at Loyola University New Orleans, the British American Drama Academy Oxford, and Queen's University Belfast, later moving to Chicago to study with Second City, and Rick Snyder. She started her career in New Orleans and continues to reside there. Cahill is best known for playing Dianne in AMC's The Walking Dead. She works with Help Heal Veterans and has started a fund, Cahill Cares, to help support important causes.