John William Siadak

October 10th, 1949March 4th, 2021

John William Siadak of Lafayette, CO passed away peacefully in his sleep at his home on March 4, 2021. He was born October 10, 1949 to the late John C. Siadak and Marguerite F. (Ortner) Siadak in Chicago, IL.

John graduated from Mendel Catholic HS in 1967, graduated from U of I (Champaign, IL) in 1971 with his teaching degree (majoring in Math). He went on to complete his Masters in Educational Psychology and worked the majority of his career (34 years) as a guidance counselor at Thornton HS in Harvey, IL. During his time at Thornton HS, he coached football, girl’s tennis, and chess, which was his passion. He loved his students and tried to give them everything they needed to succeed in life.

John met his wife, Diane (Lukosius) Siadak on a ski trip to Colorado in 1981 when they were attempting to ski in hip-deep powder on the Blue Ox run in Vail. It was love at first sight. They married 7 months later and were married for 38 years.

He retired from Thornton in 2008 when he & Diane moved to Colorado. When someone would ask what he did in retirement John would respond, “anything I want.”

John is survived by his wife Diane (Lukosius) Siadak, their 3 children, John (Amy) Siadak and granddaughter Clara of Highlands Ranch, Michael (Katie) Siadak of Denver and Emily Siadak of Lafayette, 2 sisters, Laura Siadak of Holland, MI and Mary (Tim) Jacobs of Frankfort, IL.

John enjoyed many things about Colorado, especially the abundance of craft beer. He skied and played tennis (when his knees would allow) and especially loved to play chess. He was a member of the Park Forest Chess club (in IL) and Denver Chess club.

John will be remembered by his friends and family for his gentle nature, patience, generosity, kindness and love for his family. There will be a Celebration of Life later this month via Zoom.

In lieu of flowers donations can be made in John’s name to American Heart Association or Sister Carmen Community Center in Lafayette, CO or a charity of your choice. 








Dear Diane and Family, We are deeply saddened by John's passing ~ We have many fond memories of John, especially John mimicking Roy Orbison and always winning at Scrabble. Our thoughts and prayers are with you. Please accept our deepest sympathy. Warmest regards, Jim Blair and Marcia Zmuda
I am so sorry to hear about John. I worked with him many moons ago at Thornton Township High School. He is one of the kindest people I know.