Thomas Mattson

Thomas “Tom” James Mattson, 58, of Green Bay, Wisconsin, passed away unexpectedly from a heart attack on Monday, January 26, 2026, just two weeks after undergoing surgery for a broken leg at a local hospital.

Born in Chicago to the late Dr. James and Heidi Mattson, Thomas’s early life was shaped by frequent moves. He lived in Okinawa, Japan where his dad served as a physician at the U.S. Army Hospital at Camp Zama and in Los Angeles, where his sister, Nancy, was born before returning to Chicago and ultimately settling in Green Bay. There, his brother Andrew was born, and his father established his medical practice.

Thomas was best known as a wind farm developer, contributing significantly to renewable energy projects in Wisconsin and South Dakota. He was committed to advancing wind farm development and, in his spare time, worked on the intricate design of battleships. He was also a devoted chess player who relished the game’s strategy, foresight, and quiet mental challenges.

He cherished his extended time living in London, where he immersed himself in the vibrant theatre scene, and in Taiwan, where he was drawn to its rich culture and history.

Thomas was a devoted Green Bay Packers fan, a proud Squire from Abbot Pennings High School, and always planned to own a high-rise condo in Chicago.

Thomas will be remembered as a man of deep faith, intellectual integrity, and genuine kindness.

Thomas is survived by his sister, Nancy Mattson (Patrick Szalanski), his Uncle Ken Clark (Kathy), Aunt Marliese Romaneck; cousins: Gregory Romaneck (Jane), Laura Sullivan (Frank), Steve Mattson (Lisa), Melinda Mattson, Ryan Clark, Matthew Clark (Hannah Agnes), Megan (Riley) Bredesen, Allison Mattson, Brandynn Sullivan, Flora Clark, Kyle (Crystal) Romaneck, Erin (Joe) Fannon, Colin (Amanda) Romaneck.

Thomas is preceded in death by his parents, Jim and Heidi Mattson, his brother, Andrew, grandparents, Anna and William Kuepper, Gladys and Floyd Clark and Cyrus Mattson, Aunt, Eric Striebeck, Merle and Sandy Mattson, Uncle, George Romaneck, Dick Lawrence.

A short prayer service will be held at noon on March 21, 2026, at Cotter Funeral Home, 860 N. Webster Ave, De Pere, followed by a Christian burial at Allouez Cemetery.

In lieu of flowers, donations may be made in Thomas’s name to the Andrew Mattson Memorial Scholarship at Notre Dame Academy of Green Bay. In loving memory of Thomas, his warm blankets, jackets, and clothing were donated to St. John’s Homeless Shelter, offering comfort and warmth to those in need.