William "Bill" J. Mammosser

William Joseph Mammosser, age 88, passed away peacefully on Easter Sunday, April 20, 2025, at Lightways Hospice in Joliet, Illinois, surrounded by his loving family.

Born and raised in Joliet, a 1951 graduate of St. John the Baptist Grade School, a 1955 graduate of Joliet Central High School where he met his sweetheart, Jean, whom he married in 1958.

Bill lived a life rooted in love and service. He entered the US Naval Reserves in 1953 and was later stationed at Glenview Naval Air Station until his honorable discharge as an AT2 in 1959. He then went to work for his father-in-law at The Book Shop, Inc. (later named Markelz Office Products). In 1980, he founded WJM Business Products with locations in Plainfield and Yorkville. At that time, he was active in the Plainfield Chamber of Commerce and was instrumental in establishing the first Plainfield Fest. He held various offices in the Plainfield Lion’s Club, becoming President in 1976 and earning the coveted Melvin Jones Fellowship Award, the highest form of recognition and dedication to humanitarian service. His service to God began as a server at St. John the Baptist Church and continued after his marriage to Jean. He was a member of the Cathedral Men’s Club, the CFM Family Movement and he and Jean opened their home to teach Religious Education to Catholic students attending public high school in the early 1970s. In later years, he taught R.E. at the Cathedral of St. Raymond grade school and was also a Eucharistic Minister and Lector. He was an active member of the Boy Scouts of America Rainbow Council, serving as Scoutmaster of Troop 26 at St. Raymonds when his sons were in scouting. After retirement, he felt a call to go back to scouting and became a board member of the Joliet Diocese Catholic Committee on Scouting (JDCCS) and Religious Emblems Coordinator. He taught the Ad Altre Dei and Pope Pius XII Awards to scout youth in the Religious Emblems Program and was a believer in the Scout Oath & Law and “Duty to God” program. Bill was an active member of the Cathedral Fishers of Men program, which transitioned to St. Jude’s Church and eventually to the Queen of Apostles Church. In 2019, he joined the Knights of Colombus Joliet Council #10637 to enforce their core principles of charity, unity, fraternity, and patriotism, which instilled his love of God, country, and family.

He was loved by so many and cherished by his family and friends. He was a man of immense faith and will be remembered by his legacy of leadership, compassion, love, and unwavering dedication. The love he shared will continue to live on in all who were lucky enough to know him.

Survived by his devoted wife and best friend of 66 years, Jean E. (Markelz) Mammosser; his six treasured children: Mark (Wendy) Mammosser, David Mammosser, Brian (Albina) Mammosser, Gail (Michael) Fry, Lori Mammosser, Nancy Mammosser; his cherished grandchildren: Joseph (Ashley) Mammosser, Jack Mammosser, Katie (Jesse) Severson,

Elizabeth (Isaiah) Woodruff, Alexandra Fry, Nathan Fry; his adored great-grandchildren: Maddox Mammosser, Gavin Mammosser, baby Shay Woodruff; loving siblings, Joan Jerome, Gerald Mammosser, James Floyd; sister-in-law Sharon Mammosser; and many nieces, nephews, cousins, beloved family members and friends also survive.

Bill is proceeded in death by his parents, William J. “Bud” Mammosser and Alyce M. (Hutton) Mammosser; Jean’s parents, Anthony and Angela (Kostelz) Markelz; his siblings, Judith (Ray) Speckman, Thomas Mammosser; infant granddaughter, Emily Irene Mammosser; and brothers and sister-in laws Dr. Robert (Evelyn) Markelz, Jack (Janet) Markelz, James (Marge) Markelz.

The family would appreciate memorial gifts in Bill’s name to support the organizations that were near and dear to his heart: The Chapel Renovation at Rainbow Scout Reservation, Rainbow Council 921 S. State St, Lockport, IL 60441 - your contribution will help to create a lasting space that was meaningful to Bill. Knights of Columbus Joliet Council #10637, C/O Queen of Apostles Catholic Parish, 18 Woodlawn Ave., Joliet, IL, 60435, and the Cathedral of St. Raymond Nonnatus.

The family would like to thank the wonderful team at Lightways Hospice for their care and compassion for Bill in his final days, as well as the numerous “prayer warriors” throughout his journey. We appreciate you!

Visitation will be held on Wednesday, April 30, 2025, 10:00 AM – 11:00 AM at Tezak’s Home to Celebrate Life, 1211 Plainfield Road, Joliet, IL. A memorial mass, officiated by Fr. Carl Markelz, O.Carm., will take place at 11:30 AM at the Cathedral of St. Raymond, 604 N. Raynor Ave, Joliet, followed by a private interment at Abraham Lincoln National Cemetery for committal rites and military honors. As per his wishes, cremation rites have been accorded.