John was born on Tuesday, June 25, 1946, to B.J. (“Bun”) and Dorothy (Weis) Roskos. He resided in Rapid City all his life. He passed on Sunday, July 19, 2026 at home.

His formal education had a decidedly Catholic influence. He was a member of the Class of 1964, graduating from Cathedral High School. In 1968 he graduated from the University of Notre Dame in South Bend, Indiana.

In July 1968 he joined the South Dakota Army National Guard. After completing Officer Candidate School, he received his commission in July of 1970. He was honorably discharged in 1973.

On October 6, 1973, he married Robyn Estrup in Rapid City. In 1983, he married Nannette ("Nan") Stephens. Together they welcomed two daughters, Lindsey and Amee.

John began his career at James Motors shortly after graduating from Notre Dame, working alongside his father. He later became an owner of the dealership with longtime friend and business partner, Del May, and another partner. He remained at James Motors until selling the business and retiring in 2000. During his career he served as President of the South Dakota Automobile Dealers Association, an honor that reflected the respect he earned from fellow dealers throughout the state.

John was a lifelong member of the Benevolent and Protective Order of Elks. He loved the water and spent countless hours boating and windsurfing at Lake Angostura with family and friends. He also enjoyed time at Lake Okoboji and in Florida. He loved to travel and especially enjoyed spending time in Arizona. The only thing wrong with Arizona, he joked, was that there was no ocean. Whether at the lake or gathered with those he cared about, he was happiest enjoying good company and making lasting memories.

Above all else, John was proud of his daughters. Watching Lindsey and Amee grow into the women they became was the greatest joy of his life. Their happiness and accomplishments brought him immeasurable pride, and he cherished the time spent with them.

Those who knew John will remember his quick wit, clever sense of humor, and fun-loving nature. He had a gift for making people laugh and was the kind of person others looked forward to spending time with.

John was preceded in death by his beloved wife Nan and his niece Jennifer Giacometto.

John is survived by his daughters, Lindsey (Billy Clucas) Roskos and Amee Roskos; his sister, Mary Jane (Robert) Giacometto; his brother-in-law, Steve (Vicki) Stephens; his sisters-in-law, Sandy Parker and Lorri (Tim) Amsden; and numerous nieces and nephews, including James Giacometto, Kaci Stephens, Rob Parker, Stephanie Parker, Erin Gibson, Malissa Custer, and Krista Pierce.

He leaves behind a lifetime of friendships, countless stories, and memories that will continue to bring smiles to those who knew him.

Funeral services will be held on Friday, July 24, 2026, at 10:00 a.m. at Osheim & Schmidt Funeral Home. Burial will follow at Mount Calvary Cemetery. Family and friends are then invited to gather for luncheon and fellowship at the Rapid City Elks Lodge. In lieu of flowers, memorial donations may be made to the charity of the one's choice.