Lester W. Finkle served 37 years with the Law Office of the Cook County Public Defender, first as a front-line trial attorney at Juvenile Court and then as a felony trial attorney at the George N. Leighton Criminal Courts Building, before moving to the Public Defender's appeals division, where he handled more than 600 indigent appeals over the course of 25 years. Lester joined the Public Defender's management in 2003, ultimately rising to be Chief of Staff for the Cook County Public Defender from 2015 to 2021.

Since 1997, Lester has served and continues to serve as an adjunct professor at the University of Illinois Chicago School of Law (formerly known as John Marshall Law School), where he teaches legal writing and appellate advocacy, and also coaches numerous moot court teams. From 2007 to 2014, Lester also taught appellate advocacy and legal writing as an adjunct professor at Loyola University Chicago School of Law.

Since 2022, Lester has been Of Counsel to the Chicago office of Quintairos, Prieto, Wood & Boyer, focusing his area of practice on appellate law.

In addition to dedicating a majority of his life to public defense, Lester continues to act as mentor, supporter, and friend to the more than 1,000 students he has taught over the years. In law, Lester believes that clients must always come first. In life, Lester subscribes to the philosophy that we learn by teaching, and that by helping others, we help ourselves. Lester is a lifelong resident of Illinois.