Kostas S. Hassiotis was born in Viniani, Evrytanias in 1956 to Spiros Hassiotis (1925-2004) and Anthoula (Bakogiannis, 1928-2020). Kostas has one sister Athina (born 1953). His grandfather Konstantinos Hassiotis had immigrated to America in 1920, but his stay in America was brief and details are scarce. His father Spiro immigrated to America in 1965, and settled in Greenville, South Carolina, where he and his brothers Chris and George operated the Boston Lunch in downtown Greenville.

Spiro made provisions in 1972 to bring Anthoula and his two children to reunite in Greenville. Although Kostas helped at the Boston Lunch, he and his sister Athina wanted to further their education by attending college. Kostas married in 1979, and went on to have a family with twin boys: Spiro and Kosta. As of the time of writing this, he still lives in Greenville. His sister Athina moved back to Karpenisi in 1978, and married Nikos Koudounas the following year. ADDENDUM On Kostas' grandmother and her familial connections to Elvis Presley's physician Konstantinos Hassiotis' wife Athina Nikopoulos was born in Kalesmeno, Evrytanias. Her brother Konstaninos Georgiou Nikopoulos (1896-1979) immigrated to America in 1925 on the SS Martha Washington. He and his wife Persiphoni (1905-1995) had two children: George C. Nichopoulos (born in Ridgeway, Pennsylvania) and Evangelia [(Skouteris) born in Anniston, Alabama]. George C. Nichopoulos pursued an education in medicine, and eventually became the personal doctor of Elvis Presley.