John William Andersen, affectionately known to family and friends as "Pops" and "Big Bill," passed away peacefully in his sleep on June 21, 2026, at the age of 88.
John was born on June 3, 1938 in Evanston, Illinois, to Robert and Catherine Bernice Manning Andersen. He attended Evanston Township High School and Lake Forest College. In 1964, Bill married Dulce Ann Willison and always said marrying Dulce was the best decision he ever made. Together they built a loving family that remained the center of his world. He began his career in the Treasurers office of Marshall Field & Company in Chicago before moving his family to Oshkosh to be closer to the place they loved most-Door County. He became Vice President of Finance at Wisconsin National Life Insurance Company and enjoyed a distinguished career in business and community leadership. He served on the Board of Directors of Wisconsin National Life Insurance Company, the Buckstaff Company, and for 35 years on the Board of Directors of Oshkosh Corporation.
John also believed deeply in giving back to his community. He served as pro bono treasurer of the Oshkosh Chamber of Commerce, was a lifetime trustee of the Paine Art Center, and was a Patron donor to the United Way in Oshkosh.
He was the beloved husband of Dulce Willison Andersen; devoted father of William Spencer Andersen (Heather Curtis Andersen) and David Galloway Andersen (Kimberly Martin Andersen); and proud grandfather of Lizi, Matthew, Megan, Topher, and Will Andersen. He is also survived by his sisters, Karen Andersen and Betsy LaFontaine, along with many cherished nieces, nephews, extended family members, and dear friends.
John will be remembered for his sweet smile, quick wit, remarkable intellect, and his uncanny ability to offer wisdom, guidance, or a practical solution to nearly any problem-whether of the heart or the household. He found great joy in spending time with his family, golfing with his late brother Jon, fishing with his sons and grandchildren, and enthusiastically following his beloved Chicago Cubs and Chicago Bears. Above all, John's greatest pride was his family.
His kindness, generosity, humor, and steady presence enriched the lives of everyone who knew him. He will be deeply missed and forever remembered by his family, friends, and all whose lives he touched.
A visitation and celebration of John's life will be announced at a later date.
In lieu of flowers, memorial donations may be made to the Cystic Fibrosis Foundation https://give.cff.org/tribute/johnandersen. Casperson Funeral Home & Cremation Services, LLC in Sister Bay, Wisconsin is assisting the Andersen family. Expressions of sympathy, memories, and photos of John may be shared with his family through his tribute page at www.CaspersonFuneralHome.com.
