Born and raised in rural Manitoba, Kostyshyn graduated from Ethelbert High School in 1974, where his children also attended. For the past 26 years, Kostyshyn has worked on the family farm consisting of a 200 cow/calf operation with 2560 acres. He has served as Reeve of the RM of Mossey River and on council for two decades. He has also served on various boards including the Association of Manitoba Municipalities, Manitoba Conservation Commission, Intermountain Conservation District, Ethelbert District Veterinary Board, Farm Stewardship Association of Manitoba, and the Ethelbert Curling Club and Skating Rink.
Kostyshyn lives in the Ethelbert area and is married to his wife Judy. They have two adult daughters and one grandson.[2]