James Francis Duffy Jr., 91, of Black Creek, WI, died on Sunday, Dec. 29, 2024, in Appleton, WI, due to a sudden illness after overcoming a five-year battle with cancer, thanks in large part to the exceptional efforts of ThedaCare and the outstanding care provided by Dr. S. Schmidt and team.
Burial was held at St. Mary’s cemetery in Appleton, WI. A celebration of life service will be held on Thursday, Jan. 9, at 3 p.m. at Community Bible Church, located at 402 W Forest St. in Black Creek, WI.
Mr. Duffy was born in Chicago in 1933 to James F. Duffy Sr. and Mildred Duffy in Oak Park. He attended high school at Culver Military Academy in Indiana. He then attended MIT earning both a bachelor’s and master’s in engineering and mathematics. He went on to pursue a doctorate in mathematics from the University of Chicago. Mr. Duffy then entered the Air Force where he served on mission critical assignments for the Air Force and Naval Intelligence, as well as the NSA where he [redacted].
Mr. Duffy met the love of his life, Mary Ellen (Melon) Machado, daughter of Dr. and Mrs. Walter E. Machado through a mutual family friend, Marion Hill. He pursued Mary Ellen for five years before they married on Nov. 24, 1962, officiated by the Rev. Finnegan at St. Theresa’s Parish of West Roxbury, MA. Dorothy Machado served as maid of honor and Frank Lewandowski of New York served as best man. They had recently celebrated 62 years of marriage.
Once married, Mr. Duffy spent the majority of his career with Kimberly Clark where he worked in computer engineering, pioneering operating systems for large computer systems and manufacturing software. In 1981, he started CFE or Christian Family Enterprises where he invented hardware/software for the deaf as well as provided technical solutions to long haul trucking logistic companies.
Mr. Duffy eventually returned to work at KimTech as a senior systems engineer. After retiring, he spent some time developing car wash systems and pursuing his many hobbies which included building telescopes, one of which was recognized in Sky and Telescope magazine (Dec. 2014). He also spent many hours studying the Bible, computer programming, swimming and keeping up with their home and pool as well as earning his General Amateur Radio License, call sign KD9UIB.
Mr. Duffy was very active in many churches through his life; he and his wife spent many hours engaged in church activities and mentoring pastors and young families as an ordained minister. He loved Jesus Christ with all his heart and lived his life as a devoted follower of Christ. His faith was the foundation of everything he did, and his life reflected the teachings and love of his Savior.
In addition to being survived by his wife, Mary Ellen Duffy, and his sister, Virginia Peschke, Mr. Duffy is survived by 13 of his 14 children, Marie Erm, (Patrick) of Coos Bay, OR, James Duffy of Hudson, WI, Michael Duffy of Cape Coral, FL, Judy Farm (Eric) of Coos Bay, OR, Dr. Sean Duffy (Julie) of Cape Coral, FL, Dave Duffy (Desiree) of Norman, OK, Dr. Benjamin J. Duffy (Kristin) of Harrison, WI, Liz Duffy (John Connell) of Tigard, OR, Eddie Monroe (Troy Kugel) of Appleton, WI, Ruth Duffy of Kaukauna, WI, Josh Duffy of Appleton, WI; Paul Duffy of Black Creek, WI, and Anthony Duffy of Neenah, WI; 25 grandchildren; and seven (with an eighth on the way) great-grandchildren, Danielle Erm, Pamela Baldwerm, Kyle Erm, Becky Duffy, James Duffy, Sammy Duffy, Angelina Duffy, Patrick Duffy, Eddie Metcalf, Macy Metcalf, Raegan Farm, Olivia Duffy, Katie Lubner (with a bun in the oven), Sara Duffy, Bree Swider, Mase Duffy, Mera Duffy, Grey Duffy, Jazmyn Connell, Matthew Jayarathne and Abigail Jayarathne of Litchfield, Mackenzie Monroe, Ari Monroe, Ava Monroe, Ark Duffy and great-grandchildren Orion Slack, Athena-Marie Slack, Andromeda Slack, Ella Swider, Lad Swider, Yani Swider and Luke Swider, and on the way, Lubner.
He was preceded in death by his mother, Mildred; father, James Sr.; sister, Mary McMahon; and his daughter, Deborah (Duffy) Jayarathne.
For online condolences, please visit www.valleyfh.com.
