William Joseph Kostecki, aged 98, passed away peacefully at home January 21, 2026, in Tinley Park, IL. Born March 1, 1927 in Chicago, William was known for his kind, friendly nature, and an exceptional sense of humor that brought laughter to all who knew him.
William proudly served in the US Navy in WWII from March 1945 to August 1946, and the US Air Corps in the Korean war from August 1950 to May 1952, where he dedicated himself to his duties with vigor and patriotism. After his military service, he pursued a career in education, profoundly impacting many young lives as a Physical Education instructor at Central Junior High School and Hillcrest High School, coaching gymnastics, volleyball, swimming, baseball, track & field, and cross country, as well as teaching Driver's Education.
His loving wife of 57 years, Bessie I. Kostecki, preceded him in death, along with his siblings Eugene, Adolph, Walter, John, Frank, Sophie, Albina, and Helen. He is survived by his sons, William J. Jr. (Sharon), and Keith N. (Jenn) Kostecki; grandsons Christopher (Sara) and Jeffrey (Chie) Cogswell; and great-grandchildren Logan, Lillyann, Maya, and Emiko.
William's educational journey began at Cyrus H. McCormick Elementary School, continued at Farragut Career Academy, Northern Illinois University and University of Illinois, earning degrees in Physical Education. Beyond his professional and military engagements, William cherished spending time with family and friends, enjoying his cabin on Ham Lake in Danbury, Wisconsin, walking and exercising, painting watercolors, and hand-making birthday/holiday cards for his loved ones.
William's life will be honored through private cremation and burial. Contributions in memory of William can be made to Sokol Spirit in Brookfield, Illinois, available at sokolspirit.org, supporting an organization close to his heart.
William proudly served in the US Navy in WWII from March 1945 to August 1946, and the US Air Corps in the Korean war from August 1950 to May 1952, where he dedicated himself to his duties with vigor and patriotism. After his military service, he pursued a career in education, profoundly impacting many young lives as a Physical Education instructor at Central Junior High School and Hillcrest High School, coaching gymnastics, volleyball, swimming, baseball, track & field, and cross country, as well as teaching Driver's Education.
His loving wife of 57 years, Bessie I. Kostecki, preceded him in death, along with his siblings Eugene, Adolph, Walter, John, Frank, Sophie, Albina, and Helen. He is survived by his sons, William J. Jr. (Sharon), and Keith N. (Jenn) Kostecki; grandsons Christopher (Sara) and Jeffrey (Chie) Cogswell; and great-grandchildren Logan, Lillyann, Maya, and Emiko.
William's educational journey began at Cyrus H. McCormick Elementary School, continued at Farragut Career Academy, Northern Illinois University and University of Illinois, earning degrees in Physical Education. Beyond his professional and military engagements, William cherished spending time with family and friends, enjoying his cabin on Ham Lake in Danbury, Wisconsin, walking and exercising, painting watercolors, and hand-making birthday/holiday cards for his loved ones.
William's life will be honored through private cremation and burial. Contributions in memory of William can be made to Sokol Spirit in Brookfield, Illinois, available at sokolspirit.org, supporting an organization close to his heart.
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