Margaret J. Mullen graduated with a B.A. from Illinois State University and a J.D. with Distinction from the John Marshall Law School (n/k/a the University of Illinois Chicago School of Law), where she was an editor of the law review. She became an experienced litigator as an Assistant State’s Attorney and in the private practice of law. Appointed to the bench in Lake County in 1992, she served as Chief Judge and as Presiding Judge of the Law Division, the Consolidated Family Division, and the Juvenile Division. Judge Mullen retired from the trial bench in 2017, and in 2019-20 she was President of the Illinois Judges Association. She has taught extensively in judicial education and as an adjunct instructor at the College of Lake County and at Loyola University Chicago. In 2023, she was assigned to the Illinois Appellate Court, Second District. She lives in Lake County with her husband and together they have six children.