Donna (Koessl) Steller, 86 of Sister Bay passed away on August 21, 2026, at Serenity Springs Senior Living Center at Scandia Village in Sister Bay. She was born January 23, 1940, in Sturgeon Bay, the daughter of Edward and Olive (Bhirdo) Koessl. Donna spent her childhood growing up on the family farm which is now Birchwood Lodge. After graduating from Gibraltar High School in 1958, she moved to Illinois to be a live-in nanny for three years before returning home. On May 12, 1962, she married Don Steller and moved to Milwaukee where Don and his father owned Steller's Jewelers and the Diamond Store. They bought their first house in Brown Deer where she would meet her lifelong friends Karl and Kathy Kramoris. In 1972, she would move to Menomonee Falls where she would work for McDonalds for 23 years, retiring in 1999. After retiring, she and Don would move back to Sister Bay and build a house on land her dad acquired for a milking cow in the depression. Donna always loved the outdoors, and you could find her working in her flower beds and garden. She also spent countless hours canning the things she grew. She always had a love for animals and had everything from dogs, rabbits and guinea pig. Her last dog Pearl was her constant companion in her later years. Mom was always very family-oriented and loved getting us together for the holidays. She would make large meals and afterwords we would play games. She especially loved cards, her favorites were the 10 game, kings in the corners (with the great-grandchildren) and cribbage. Donna will be missed by her sons, Marlin (Tammy Freis) Steller of Kiel, and Jeff (Cheryl) Steller of Sussex: daughters, Kathy (Duane) Sitte of Sister Bay, and Susan (Dave) Mercier of Rubicon; grandchildren, Marlin Steller JR, Jason Steller, Nicholas (Jamie) Steller, Tristan (Navaeh Ostenson) Steller, Laurie (Joe) Stafford, Michael (Brittany) Sitte, DJ Sitte, Amber Sitte, Amelia (Jake) Dueppen, and Amanda Bertoni; great-grandchildren, Shyann, Denver, Nicholas, Mac, Lilith, Jasmine, Jerimiah, James, Brooklyn, Adrian, Wesley, Aaron Stafford, and Briar Sitte. She is also survived by her brother, Joseph Koessl; sister-in-law, Vicky Pate; and nieces and nephew. She is preceded in death by her husband of 52 years, Don; her parents, Edward and Olive; her brother and sister-in-law, Jerome and Patricia Koessl; sister-in-law, Vicki Koessl; nephews, Edward, and Bill Koessl; and her granddaughter, Aimee Bertoni. Donna's life will be honored with a Mass of Christian Burial prayed at 11:00 a.m. on Tuesday, September 8, 2026 at Stella Maris Parish – Sister Bay site, 2410 S Bayshore Dr, Sister Bay, with visitation beginning at 10:00 a.m. until 10:45 a.m. with Fr. Jerry Pastors officiating. She will be laid to rest in St. Rosalia Cemetery in Sister Bay. Casperson Funeral Home & Cremation Services, LLC in Sister Bay is assisting the Steller family. Expressions of sympathy, memories, and photos of Donna may be shared with her family through her tribute page at www.CaspersonFuneralHome.com.