Donn LeRoy Klingler

Donn LeRoy Klingler, son of Carl and Arlene (Schmidt) Klingler, was born in Cedar Rapids, Iowa on May 24, 1931. He passed away on March 27, 2026. After high school in Charleston, Illinois, he served in the Air Force during the Korean War. Donn then attended the University of Illinois on the GI Bill. As he worked towards his degree in mathematics, he also played the clarinet as the corner of the second L in the Illinois marching band. At the university, he met Elizabeth “Lizzie” Learner. On his graduation day, he and Lizzie skipped the ceremony to get married, a union that would last sixty-two years and produce three children, Richard, Jean, and Lisa (Looke), and seven grandchildren.

Donn devoted his life to his family and to his high-school math students. He started teaching at Lyons Township High School in LaGrange, Illinois. He then went to graduate school at The University of Michigan, where he earned his master’s degree, completed the coursework for a doctorate, and co-authored a high school algebra textbook. From there, he taught in private schools, with stints at Kent School in Connecticut, The Fountain Valley School in Colorado Springs, and Cincinnati Country Day School in Cincinnati, Ohio, where he served in many roles: math department chair, advisor, class dean, and college counselor. His students remember his mastery of his subject and his ability to make mathematics both accessible and enjoyable. For decades after his retirement, former students continued to contact him to thank him for his guidance. His colleagues remember him as an excellent teacher, a problem solver, a man of integrity, and a great friend.

He and Lizzie worked at CCDS until their retirement to New Hampshire. There, Donn immersed himself in gardening, the KUUF Unitarian community, and the serious business of providing a home base for his grandchildren, complete with fishing adventures in the summer and sledding and skiing in the winter. Donn lived out his days with undimmed intellectual curiosity, a desire to be useful, a restlessness born of a sense that there was still a world to explore, and a fundamental kindness that he extended to all he encountered. He is survived by his brother, Clyde Klingler, his children, Richard and Jean, their children and those of his daughter Lisa, and thousands of students lucky enough to have had him as a teacher.

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