[1] He received a Bachelor of Arts degree from Idaho State University (ISU) in Pocatello in 1974,[2] where he was student body president.

[2] Winmill granted the habeas corpus petition of Charles Fain, a wrongfully convicted man who spent 18 years on Idaho's death row.

[1] In 1999, Winmill presided over the trial of Allan Elias, a southeastern Idaho businessman, on charges of arising from 1996 incident in which Elias ordered an employee, who lacked safety training or proper protective equipment, to clean the inside of a large tank that stored a toxic mixture of phosphoric acid and cyanide.

[12][13] In Animal Legal Defense Fund v. Otter (2015), Winmill struck down the "ag gag" law passed by the Idaho Legislature in 2012, ruling that the statute—which, among other things, banned the audio or visual recording of agricultural operations—violated the Free Speech Clause of the First Amendment to the United States Constitution.

[1] He has served as a member of the board of the Idaho Humanities Council; as a member of the Board of Visitors of Brigham Young University's J. Reuben Clark Law School; and as a co-founder of the Idaho Legal History Society, which sponsored the performance of an original play marking the hundredth anniversary of the high-profile trial of Big Bill Haywood.