James F. Duffy Jr.

James Francis Duffy Jr. (91) of Black Creek, WI, passed away on Sunday, December 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 & team.

James F. Duffy Jr. was born in Chicago, Illinois in 1933 to James F. Duffy Sr., and Mildred Duffy in Oak Park, IL. James attended high school at Culver Military Academy, Indiana. He then attended MIT earning both a BS and Masters in Engineering & Mathematics. James went on to pursue a doctorate in mathematics from the University of Chicago. He 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].

James met the love of his life, Mary Ellen Machado (Melon) daughter of Dr. & Mrs. Walter E Machado through a mutual family friend, Marion Hill. He pursued Mary Ellen for five years before they married on November 24, 1962, officiated by Reverend Finnegan at St. Theresa’s Parish of West Roxbury, MA. Dorothy Machado served as maid of honor and Frank Lewandowski (NY) served as best man. James and Mary Ellen recently celebrated 62 years of marriage.

In addition to being survived by his wife, Mary Ellen Duffy, and his sister, Virginia Peschke, in the style of Leviticus, here is the genealogy of James' surviving progeny: 13 of his 14 children - Marie Erm, (Patrick) of Coos Bay, Ore; James Duffy of Hudson, WI; Michael Duffy of Cape Coral, FL; Judy Farm (Eric) of Coos Bay, Ore; Dr. Sean Duffy (Julie) Cape Coral, FL; Dave Duffy (Desiree) Norman, OK; Dr. Benjamin J Duffy (Kristin) Harrison, WI.; Liz Duffy (John Connell) Tigard, Ore.; Eddie Monroe (Troy Kugel) Appleton, WI.; Ruth Duffy, Kaukauna, WI.; Josh Duffy, Appleton, WI.; Paul Duffy, Black Creek, WI.; and Anthony Duffy, Neenah, WI. He will be missed by his 25 grandchildren and 7 (+bun) 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, Abigail Jayarathne; 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 (bun) Lubner.

James was preceded in death by his mother Mildred, father James Sr., sister Mary McMahon and his daughter Deborah (Duffy) Jayarathne.

Once married, James spent the majority of his career with Kimberly Clark where he worked in computer engineering, pioneering OS for large computer systems and manufacturing software. In 1981 James 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. James 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.

 James was very active in many churches through his life; he and Mary Ellen spent many hours engaged in church activities and mentoring pastors and young families as an ordained Minister. James 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.

James was buried at St. Mary’s cemetery in Appleton, WI. A celebration of life service will be held on Thursday, January 9, 2025 at 3 p.m. at Community Bible Church, 402 W Forest St., Black Creek, WI 54106. For online condolences, please visit www.valleyfh.com

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