John Schneller

John Louis “Duke” Schneller, 89, of Custer, S.D., passed away peacefully surrounded by family Feb. 4, 2026. A man of deep faith, ingenuity, and humor, Duke lived a life dedicated to his Catholic faith, his country, his family and his profession.
John (Duke) Louis Schneller was born in Dennison, Iowa, March 23, 1936, to William Schneller and Marie (Cermac) Schneller. He passed away Feb. 4, 2026, in Custer. 
Rosary and viewing will be celebrated Friday, Feb. 13 at 6 p.m., followed by a Vigil service at 7 p.m. Mass of Christian Burial will be celebrated at 10 a.m. Saturday, Feb. 14. These services will be held at St. John the Baptist in Custer. 
Interment will take place with military honors at the National Cemetery near Sturgis, S.D., Monday, Feb. 16 at 9 a.m.
Born in Denison, Iowa on March 23, 1936, to William “Bill” and Marie (Cermac) Schneller, he was the second of four children. He served in the U.S. Air Force from 1954 to 1958, where he picked up the nickname “Duke.” He earned the title “Airman of the Year” and a faculty position at the U.S. Air Force Academy for developing a prototype communication tester for American pilots that is still being used today.
After his military service, Duke earned his doctorate in Dental Science from Creighton University where he also met and married his beloved wife, Mary “Peggy” (Blomstrom) in 1961. The couple eventually moved to Belle Fourche, S.D. Here was born to them five children: Jean, Joe, Ann, Dan and Tom. Two children, Elizabeth and David, sadly died before birth.
During this time, Duke and Peg shared their Catholic faith in many remarkable ways. Duke also obtained his pilot’s license and brought much-needed dental care to the remote communities of Faith, Kadoka, Bison, Buffalo, and later, Martin, S.D. This also inspired later trips to Mexico as a medical missionary.
In 1977 the family moved for a short time to Tempe, Ariz., where their sixth surviving son was born, James Michael. In 1979, they returned to Rapid City, S.D.—always with the intent of serving the Lord and living their faith.
In 2000 Duke retired from private practice and moved to Custer. He renewed his dental license and began to work with the state and federal penal system, first at STAR Academy and then in Rapid City. When he finally retired from dental practice, he had a cumulative record of over 53 years in healing and helping people smile.
After over 50 years of marriage, Peg died in 2012. It was shortly after this that Duke found love again. He married Gayle Kocer (Lessert) of Martin in November 2013. Both Duke and Gayle have been active members of St. John the Baptist parish in Custer, where, until his death, Duke attended daily Mass and Morning Prayer, was active in the pro-life prayer group, led the weekly Sunday Rosary, prayed ardently for the souls in Purgatory and was a member of the Knights of Columbus.
Duke passed away from complications with Parkinson’s disease on Wednesday, Feb. 4.
He is survived by his wife, Gayle Schneller; his sister, Susie (Gary Howell); his children, Jean (Kent) French, Brenda (widow of Joseph) Schneller, Ann (John) Dvorak, Dan (Jill) Schneller, Tom (Bobbie) Schneller and James Schneller; his stepchildren, Joan (Rock) Risse, Jean (Jay) Peterson, Kathy (Julio) Medeiros and John Kocer; his grandchildren, Sarah, Christine, John, Steven, Michael, Katherine, Rachael, Joshua, Jacob, Bridget, Joseph, Matthew, Josie, Dominic, Kylee, Heidi, Hans, Luke, Lance, Blaze, Eric, Ian and Ethan; a large, loving legacy of great-grandchildren; his stepgrandchildren, Elie Risse-Goings, Sam Risse, Chelsey Risse, Jimi Risse, Ben Risse, Roy Risse, Mary Risse, Isabel Risse, Lexie Sobolewski, Justin Peterson, Carlie Armstrong, Sylvia Smith, Dean Smith, Brandon Jensen, Taylor Rains, Jaxon Phillips and Dillon Phillips.
He was preceded in death by his parents, brother, Charlie; sister, Kaye; his first wife, Peggy; son, Joseph; and grandson, Jacob French.
Arrangements have been placed in the care of Chamberlain McColley’s Funeral Home in Custer.