70/30 Productions

Adam Reed and Matt Thompson, the creators and writers of Sealab 2021, came up with the idea for the show in 1995 while they were production assistants for Cartoon Network. They stumbled on a tape of the show Sealab 2020, and wrote replacement dialogue. Cartoon Network passed on the show because it did not believe it was funny. Five years after quitting Cartoon Network, the two went back to the original tape, this time making the characters do what they wanted. Cartoon Network bought the show, coincidentally around the same time that Adult Swim was created. The original "pitch pilot" is available on the Season 1 DVD as a special feature. The series was produced at 70/30 Productions, a studio founded by Reed and Thompson located at Atlanta.

Very few of the episodes of the series share any continuity or ongoing plot. For instance, the entire installation is destroyed at the end of many episodes, and crew members are often killed in various ways, only to return in the following episode. There are occasional running gags, such as the "Grizzlebee's" restaurant chain, a parody of Applebee's and Bennigan's, the character of Sharko, and Prescott, the half-man, half-tentacle monster "from the network". It contains many references to the pop culture of the 1980s–2000s and makes use of other cartoons from the 1970s besides that on which it is based, such as 1973's Butch Cassidy for the on-screen appearances of the Sealab writers, and various one-off appearances of other characters.