Diane was the only child born to John and Elaine Welsh in Snohomish, WA on May 11, 1942, remaining there through her grade school and high school years. She pursued a college prep course in high school and enjoyed most of her classes. Her outside interests included piano playing, following more than 10 years as an accordionist; singing in various church and school groups; marching in high school drill team; starring in two school plays; involvement in school politics; and other extracurricular activities. During those years, she mostly dated Mike Johnson, Two years her senior at Snohomish High. Whom she married 2-1/2 years after completing her high school education.

Following her graduation in 1960, Diane attended approximately two years at St. Joseph School of Nursing in Tacoma, studying to become a Registered Nurse with a B.S. Degree. Being told by the school administrators that she was not tough enough and was to emotionally involved with her patients, she left school , and she and Mike Johnson were married shortly thereafter in Tacoma. They then moved to Seattle for a couple of years where she worked in the Personnel office at Boeing to earn enough money to enable Mike to return to college.

During Diane's years with her first husband, she continued office work to assist him in completing his Bachelor degree at WWSU in Bellingham, enabling him to begin his teaching career. They ended their marriage in 1970, since they were unable to have their own children. Diane attended classes and pursued her secretarial career, and she held a variety of increasingly diversified and responsible, executive-type secretarial positions in large, multi-national firms.

Diane married Mike Spellman in 1976 in Bellevue, after knowing him for several years. They shared a mutual love  for the outdoors, fishing in Canada, planting and working both in vegetable and flower gardens at their home and enjoying their dogs, cats and white bantam chickens. In January 1981, they transferred to the Tri-Cities, WA, where her husband was sent to be chief spokesman for a company planning to build two nuclear power plants in that area. Also at that time, Diane was accepted as the secretary for the Richland Police Chief, where she continued with her position until May 2010, when she took an emergency retirement due to her husband's illness. At that time, she was just short of her 70th birthday and only months away from 30 years with the police department. Diane died on February 28, 2023. She had no Immediate family members. She requested there be no funeral services. She and her husband Mike share a glass niche at Desert Lawn Memorial Park in Kennewick, WA.