The creator of Squid Game, Hwang Dong-hyuk, developed the show 10 years ago. However it was rejected by media companies and actors for 10 years.
The phone number used in the series was a real phone number. However, the only difference is that it has eight digits in the series, while real numbers in South Korea always have ten. When the callers dialed that number, their phones automatically added the prefix "010", which turned it into a real number. As a result, the owner of it was called more than 4,000 times a day. Netflix later announced that the number will be altered.
Chae Kyoung-sun, the set designer, felt this was her most challenging project as not only did she have to create something child-like and whimsical, but also creepy and menacing in addition to the safety concerns for the actors.
Director Hwang Dong-hyuk cast Lee Jung-jae as Gi-hun to "destroy his charismatic image portrayed in his previous roles."
The worker jumpsuits were chosen for their loose design to mask the gender of the workers and to create a colony vibe to the setting. The soldiers' masks were designed specifically to resemble the face of an ant.