Doug Harder passed peacefully on February 20, 2026, at the age of 80, after a long struggle with primary progressive aphasia (PPA), a form of dementia.
Doug is survived by Carol, his loving wife of 57 years. Loving father to Clint Harder, Dana Coulthurst, Cindy (Brian) Adam, Debbie (Brian) Grall, and Linda Sanders & Scott Coulthurst.
Caring Grandpa to Jake & Josie Coulthurst, Ella & Sal Sarder, Emma & Chloe Grall, and Chase & Maya Adam. He is also survived by sisters Judy Gronski & Lin Barlow, and many nieces & nephews. He was preceded in death by his parents, Richard and Arleen Harder.
Born on the South Side of Milwaukee, Doug graduated from Notre Dame High School and earned a degree in Mathematics from St. Norberts College, where he met Carol and made other lifelong friends.
Doug dedicated more than 40 years to teaching math, beginning at Cathedral High School and retiring after 39 years at Marquette High School. He loved sharing his passion for sports as a basketball and track coach. He spent part of his summers running a College Prep program preparing underserved students for Highschool. Later, he volunteered with Nativity Jesuit Academy, attending their summer camp where he patiently taught youth confidence through water skiing.
Doug was happiest on or near the water, especially in Townsend at the family property on Horn Lake. He loved to enjoy the lake with friends and family where he was always available to take people waterskiing, tubing, and on boat rides to search for loons and eagles. He loved the sunsets, and sitting on his dock and watching the lake. His legacy of enjoying time with friends and family at the lake will be carried on by his loved ones.
Special thanks to the staff at Zilber Hospice.
In lieu of flowers, memorials may be made out to the Nativity Jesuit Academy, the Cathedral Center, or Marquette University High School.
Visitation will be on Monday, March 9, 2026, from 10am until time of Memorial Mass of Christian Burial at 12pm, followed by a luncheon and sharing at Good Shepherd Catholic Church (N88W17658 Christman Rd, Menomonee Falls, WI 53051).