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Dr. Gary Kristian Leaf
Sunday January 19, 2020 3:00p.m. ~ 7:00p.m.
7:00p.m. Chapel Service
Burial Location


Renowned Applied Mathematician and Physicist Dr. Gary Kristian Leaf, an employee of Argonne National Laboratory, passed away on January 13, 2020 at the age of 84. Gary was born on October 25, 1935 to Joseph Albin Leaf born in Småland Sweden and Lillian Linnea Carlson Leaf born in Daggett, Michigan. He was baptized and confirmed in the Lutheran faith. In 1948, after graduating from Nicholas Senn High School, on the North Side of Chicago, Gary went on to study Mathematics and Physics at the University of Illinois in Champaign-Urbana. It was there that he met his wife Diane Marian Deeg. Gary and Diane were married on June 6th of 1959. The couple had two children, Karen Sue Leaf and Susan Ayn Leaf. 

After graduating with a Doctorate in Mathematics and a Masters in Physics from the University of Illinois, Gary accepted a position as a Professor of Mathematics at the University of Chicago. From there he went to work at Argonne National Laboratory in the field of Physics and Applied Mathematics. Later in his career he worked in the field of Computer Science as well. Despite battling Retinitis Pigmentosa, a condition that rendered him legally blind, Gary published many scholarly papers with his colleagues at Argonne. Gary worked at Argonne for 56 years. The field of Mathematics was truly his life's passion. He worked at Argonne until the end of his life. Gary belonged to SIAM, the Society for Industrial and Applied Mathematics. He was also a member of Sigma Xi, the Scientific Research Honor Society.  

On the personal side, Gary was loved and respected by his family members. He was fiercely patriotic and loved his country. He always kept abreast of current events and could speak knowledgeably about history and many other subjects. He was a true conversationalist. Gary was always expanding his knowledge by listening to audio books. His intellect was amazing! 

Gary loved to work with German Shepherd dogs and Three Day Event horses. Having owned 13 German Shepherds over a period of 50 years, he  was a lifetime member of the German Shepherd Dog Training Club of Chicago. He also owned two Dressage horses that his daughter, Karen, competed in shows. He was very loved and respected by all of his family members.

Gary was preceded in death by his parents, Joseph and Lillian, and his siblings: Doris Virginia Leaf, Joseph Kenneth Leaf, Gordon Conrad Leaf, Lt. General Howard Wesley Leaf, Ralph Eugene Leaf, and Elaine Carlson Hiller. He is survived by his wife Diane M. Leaf, his two daughters Karen S. Leaf (Svab) and Susan A. Leaf (Jeffrey), son-in-law Richard C. Jeffrey, his four grandchildren, Jennifer Ayne Jeffrey, Jacqueline Marie Svab, Peter Benjamin Svab and Jessica Noelle Jeffrey, his great grandson Jayce Bennett Svab and his cousin Delores (Carlson) Wright of Daggett, Michigan. 

A traditional wake and funeral service for Dr. Gary K. Leaf will be held on Sunday, January 19, 2020 at the Adolf Funeral Home, 7000 S. Madison Street, Willowbrook, Illinois. The wake will take place from 3:00 PM until 7:00 PM. After the wake, a prayer service will begin at 7:00 pm at the funeral home.  

In lieu of flowers, please send donations to one or both of the the following organizations in in memory of Gary K. Leaf :

Fighting Blindness Organization: and Military Working Dog Team Support Association:


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