Although it is stated numerous times that Theo Kojak is of Greek heritage, the name "Kojak" is actually of Polish origin. Kojak's heritage was changed to Greek in order to match Telly Savalas' Greek heritage.
Telly Savalas is seen throughout the series both sucking on his lollipop and smoking. In real life, Telly Savalas was trying to quit smoking. The lollipop was used to cut back on smoking. His character Kojak even admitted once that he smoked too much and sucked on lollipops every day except on Sundays.
Telly Savalas's brother, George Savalas, had a supporting role as Detective Stavros. In the first few series he appears in the credits as 'Demosthenes', his real name in Greek. He also received a "Production Assistant" end credit but it is unclear what this involved.