William Mui

William "Bill" Mui, son of Tsui and Heung Ming Mui was born June 23, 1965 in Hong Kong. The Mui family relocated to America in 1970 when William was the young age of 4 years old and at an early age he began to assist in helping work and run the family restaurant. William was a graduate of the University of Wisconsin-Oshkosh with a Bachelor's Degree in Chemistry and began his life long career in Analytical Chemistry, where he would end up as a Senior/Lead Chemist of an analytical lab and a credited patented inventor of technology used in Huggies infant and toddler products.

William Mui, 60, of De Pere, passed away on March 13, 2026, surrounded by immediate family and wished to pay as much as he could forward with donating everything he could back to science and others in need.

Through life, William indulged in various hobbies like photography, animal raising, bodybuilding, coaching sports, and woodworking. Through all things he was always incredibly selfless, he lit up every room the brightest it's ever been wherever he went, so it's no wonder he always got the best photos. William's love for animals showed no bounds, he raised and housed fish, frogs, tortoises, iguanas, sugar gliders, mice, chameleons, saltwater reefs, turtles, eels, cats, dogs, and much more. His love for animals was also expressed through his photography where he would spend a good portion of his free time chasing eagles, ospreys, hawks, chickadees, owls, and whatever else may be grazing the skies.

William's bodybuilding journey began alongside his brother Bing, where he would regular the Oshkosh YMCA, Neenah Athletic Club, and Neenah-Menasha YMCA. One of William's greatest accomplishments was becoming the INBF Midwest Lightweight Champion in 2000. INBF is a drug free federation, where William was subject to polygraph and drug screening. No shortcuts allowed, as William wouldn't have it any other way. As time progressed, William stepped away from competition and turned to coaching various sports teams for his three boys. His dedication to them was his top priority the day he became a father. At the end of the day, the love he shared for his family was unparalleled by anything else. Not only was William a devoted husband, he always made time for his children, step children, grandchildren, and loved them unconditionally.

Selfless, strong, mentor, and a comedian are a few terms that could be used to describe William's character. He was someone who would give the shirt off his back for anyone. He helped all those he associated with, regardless of if they would reach out or just out of the kindness of his heart. Whether it be a woodworking project for a family member needing a handicap ramp, a complete stranger, or a young athlete trying to achieve their goals, he stepped up to the plate and made it his duty to go above and beyond for them. William always showcased the brightside to every situation sometimes with strength, reason, and/or laughter.

His sense of humor was unique like your favorite classic Disney cartoon. Was it dry? Yes. Was it also the funniest you've ever heard? Yes.

William Mui is survived by his wife: Julie Mui, children: Jack (Justine) Mui, Clifford (Jana) Mui, Joseph (Kayla) Mui, step-children: Michael (Caysie) Schultz, Jacob (Brooke Mahoney) Schultz, mother Tsui Mui; siblings: Macy (Pedro) Chan, Mary (Warren) Hung, Simon (Cindy) Mui, Stephen (Ping) Mui, Bing (Julie Van Den Heuvel) Mui; grandchildren: Cameron and Felix, Carter and Willow; mother-in-law Toni (Jack Mongeau) Etter; numerous nieces, nephews, cousins, other family and friends.

He was preceded in death by his father, Heung Ming Mui and father-in-law Robert Etter, Jr.

An intimate family service was held.

The Mui family extends its gratitude to Emplify by Bellin Health and Unity Hospice who provided compassion and care when it mattered most. In lieu of flowers, please make a donation in William’s honor to Happily Ever After Animal Sanctuary, Bay Beach Wildlife Sanctuary, Safe Haven Animal Rescue, or your favorite local wildlife sanctuary.