Jason Allen Tetzlaff

Jason Allen Tetzlaff, 37, of Fond du Lac, passed away unexpectedly on Saturday, May 9, 2026, with his wife by his side. He was born in Fond du Lac on September 16, 1988, the son of Lisa Mielke. On August 29, 2015, he married the love of his life, Katie, and together they welcomed three children.

Jason was employed at Mercury Marine for the last eight years. He enjoyed the people he worked with and always had good things to say about his co-workers. Jason’s three favorite things were watching football, gaming and spending time with his family. He enjoyed playing on his PS5, fantasy football, playing board games—especially Saturday nights—and spending time with his wife and kids.

He is survived by his wife, Katie Tetzlaff of Fond du Lac; two sons, Austin and Sawyer Tetzlaff, both of Fond du Lac; his mother, Lisa Mielke of Ripon; his sisters, Ashley (Brad) Mielke, and Kelly Mielke, all of Ripon; nephew, Remington Hawkins, and nieces, Cadence and Kendra Hawkins, all of Ripon; his father-in-law, Steven Groesbeck of Fond du Lac; and his two brothers-in-law, Chris (Dawn) Groesbeck, and Jim Groesbeck, all of Fond du Lac. He is further survived by aunts, uncles, cousins, many friends, and his godparents, Sherry and Reggie Bortner of Fond du Lac. Jason was preceded in death by his father, Darwin Mielke; a son, Carter Tetzlaff; his grandma, Diane Vincent; and his mother-in-law, Patricia Groesbeck.

Visitation will be held from 12:00 PM - 3:00 PM, Sunday, May 17, 2026, at Uecker-Witt Funeral Home. A memorial service will follow the visitation at the funeral home, beginning at 3:00 PM. Cremation has taken place.

The family would like to thank his cousin, Janey, and the Wisconsin Dells Police Department and EMS staff for their help.

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 ueckerwitt.com