Cover photo for Mary C. Theisen's Obituary
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1929 Mary 2023

Mary C. Theisen

May 22, 1929 — March 18, 2023

Mary Catherine Theisen, 93 of Fond du Lac entered into her eternal home on March 18, 2023, surrounded by her loving family at St. Agnes Hospital. The foundation of Mary’s life was her deep, deep faith in God which led her through many hills and valleys in her years on earth. Mary was born on May 22, 1929, a daughter to Leo and Rose Clark Ryan. Mary did what every farm child did with many chores and duties on the farm. She graduated from Campbellsport High School in 1945.

Mary married Thomas Theisen on September 13, 1952, at St. Mary’s Church in Eden. She had various jobs before working as a medical transcriptionist at St. Agnes Hospital for 32 years, retiring in 1993. After she retired from St. Agnes Hospital, she worked as a part time transcriptionist for the Family Foot Clinic for 12 years.

Mary was a fun Grandma and enjoyed her trips to the casino to play the slots and bingo. She loved nabbing unsuspecting victims on one of her favorite days of the year, April Fool’s Day. Nothing would give her greater pleasure than the grandchildren falling for one of her pranks.

Mary is survived by her four children, Gary (Karen) Theisen, Dale (Sherri) Theisen, Vicki Theisen, all of Fond du Lac and Colleen (Matthew) Schneider of Mount Calvary. She is also survived by grandchildren, Emily (Andrew) Hedman, Apple Valley, MN, Erin Theisen (Mark Robitaille), Boston MA, Amy (Bryan) Bubolz, Fond du Lac, Maria (Thomas) Sheppard, Fond du Lac, Trevor (Kristen) Theisen, Fond du Lac, Becky (Jason) Hoerth, St. Cloud, Ryan (Katie) Schneider, Milton, and Megan Schneider, Sturgeon Bay. Also surviving are great grandchildren, Roman, Bo, Charlie, Levi, Violet, Brady, Makenzie, Hudson, Genevieve and expecting her tenth great grandchild soon; and many nieces and nephews. Mary is also survived by her special companion for the past 14 years, Dale Cutler of Fond du Lac. Mary was predeceased by her husband Thomas on June 27, 1979, parents Leo and Rose, and siblings, Lester Ryan, Vincent Ryan, Joyce Ryan, and Jean Whitty in addition to special friend Ray Weyer.

Family is extremely grateful to the professional, compassionate staff of 5 West at St. Agnes Hospital and Hospice personnel.

Visitation will be at Holy Family Church on Saturday, March 25, 2023 from 10:30 AM – 12:00 PM followed by a Mass of Christian Burial at 12:00 PM. Burial will follow in Calvary Cemetery.

Memorials may be directed to SSM Health at Home Hospice – Fond du Lac or Holy Family Parish.

Services are in the care of Uecker-Witt Funeral Home, 524 North Park Avenue, Fond du Lac, WI, 54935. Additional information and guestbook can be found at

To order memorial trees or send flowers to the family in memory of Mary C. Theisen, please visit our flower store.

Service Schedule

Past Services


Saturday, March 25, 2023

10:30am - 12:00 pm (Central time)

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Funeral Service

Saturday, March 25, 2023

Starts at 12:00 pm (Central time)

Enter your phone number above to have directions sent via text. Standard text messaging rates apply.

Enter your phone number above to have directions sent via text. Standard text messaging rates apply.


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