Michael Gerald Diestelmeier

Michael G. “Mike” Diestelmeier, 66, of Sun Prairie, Wisconsin, passed away at his home on June 4, 2026. Born on April 5, 1960, in Monroe, Wisconsin, Mike lived a life marked by dedication to his family, his work, and his passions.

Mike treasured his family deeply and is survived by his son, Neil Diestelmeier; sisters, Colleen (Tim) Ward, Cheryl (John) Barman, and Debra Diestelmeier; as well as a nephew and nieces. He also leaves behind his Aunt Shirley Miller; many beloved cousins; his former wife, Karen; and close friends, Marty Voegel, Doug Hull, Kenn Beauchaine; and many others he held dear. He was preceded in death by his mother, Catherine (Seffrood) Diestelmeier; his father, Gerald Diestelmeier; as well as several cherished grandparents, aunts, uncles, and cousins who undoubtedly welcomed him with open arms. Mike’s relationships were built on kindness and warmth-qualities that endeared him to all who knew him.

After attending LaFollette High School in Madison, Mike proudly served his country in the United States Army (1978-1981) as a Special Weapons truck driver garnering the nickname of 'Mo-Gas' by fellow soldiers. Stationed in Garlstedt, Germany, he was part of the Alpha Battery, 1st Battalion, 14th Field Artillery, 2nd Armored Division and was responsible for delivering sensitive tactical artillery with additional training in demolitions. Mike played a critical role within the Special Weapons unit requiring top-secret clearances and his service exemplified his commitment to duty and excellence.

Upon completing his military service, Mike embarked on a career that spanned over four decades at Walgreens Distribution Center in Windsor where co-workers quickly became friends, especially if there was a shared passion for collector cars. During his long tenure at Walgreens, Mike also worked as a Service Advisor at Firestone Complete Auto Care and in 2014 opened his own auto repair business, South Central Automotive, in Sun Prairie with his son, Neil, and close partners. After retiring from Walgreens, Mike returned to his initial passion of truck driving enjoying dedicated daily runs to La Crosse for Sheehy Express LLC from where he recently retired in April. Mike's strong work ethic and reliability were hallmarks of his professional life.

Mike was a true car enthusiast through and through with a lifelong passion for all things automotive. He loved collecting, modifying, racing and spending countless hours working in his shop with his son. One of Mike's most cherished traditions was attending the annual Jefferson Swap Meet with Neil, where they shared unforgettable memories, discovered new treasures and often found inspiration for their next project together. His passion for automobiles was not just a hobby but a defining aspect of who he was-a man who found joy in the roar of an engine and the camaraderie of fellow enthusiasts.

Mike’s legacy is one of hard work, loyalty, and an enduring love for family and friends. His memory will live on in the hearts of those who knew him best-his son Neil especially-and through the countless lives he touched with his kindness.

The family of Mike invites friends and loved ones to join them for a Celebration of Life at the WILLOWS TAVERN in Waunakee/Westport, 5485 Willow Road, Waunakee, Wisconsin, from 2 p.m. until 6 p.m. on Sunday, June 28, 2026.  As a special tribute to Mike’s service and legacy, an Honor Guard ceremony will be held at 3:30 p.m. that day.  

In honor of Mike’s passion for automobiles, guests are encouraged to bring a special car or motorcycle they take pride in to put on display during the gathering. This will be an opportunity to share memories, tell stories, and celebrate Mike’s life with family and friends.

We look forward to coming together to remember Mike and the many ways he touched our lives.

Online condolences may be made at www.gundersonfh.com.

Gunderson East

Funeral & Cremation Care

5203 Monona Drive

(608) 221-5420