Chelios grew up in Chicago, Illinois, where his father, Constantine "Gus" Chelios, owned a chain of Greek restaurants. The family name was originally "Tselios", but Gus chose to change the family's spelling. The family moved to Poway, California, in 1977, when his father left his struggling business in Chicago to open a restaurant in the San Diego area. He was a Chicago Blackhawks fan during his childhood but was more focused on football, idolizing Chicago Bears linebacker Dick Butkus. Chelios attended Mount Carmel High School (Chicago) before his family moved west, and then finished prep studies at Mira Mesa Senior High School in San Diego.