Andy Kaufman asked the producers before he signed his contract to give guest appearances to Tony Clifton, someone he claimed was a friend of his. They agreed to give few guest appearances to Tony Clifton, and Kaufman signed the contract to play Latka. Tony Clifton showed up for the rehearsals late, very drunk and with some scantily-clad women. The producers fired Tony on his third day. Clifton was in fact one of Kaufman's characters. Although to maintain the practical joke Kaufman always denied that Clifton was not a real, separate person, he was usually (thought not always) played by Kaufman in disguise (Clifton was also occasionally played by Kaufman's friend Bob Zmuda).
On The Howard Stern Show (1990), Taxi (1978) writer Sam Simon claimed that when Jeff Conaway was absent during the production of one episode, his dialogue was reassigned to the other cast members who delivered the jokes as well or better, which made the producers realize that Conaway was expendable. Conaway left during the 4th season.
In 2013, on the NPR program "Wait Wait... Don't Tell Me!," Tony Danza said that when he auditioned for his role on Taxi, he read with Mandy Patinkin, who was auditioning for the role that ultimately went to Judd Hirsch.
In an episode during the first season, Danny DeVito's character plays violin in one scene. A photo taken during rehearsals of that episode ran in a tabloid magazine along with a story describing how De Vito is "giving up" acting to play violin. De Vito's relatives called him out of concern believing the story was true.
The producers originally wanted an African-American actor to play Bobby. Cleavon Little was a finalist for the part. Jeff Conaway was originally considered to play John but asked to audition for Bobby. Conaway was the only white actor who was considered for the role.
Andy Kaufman's contract stipulated that he only had to be on the set two days a week, 14 episodes per season. Kaufman disliked sitcoms and originally turned down the part of Latka because he wanted to focus on his stand-up comedy career. But the producers liked him so much that a compromise was reached.
The theme song's title, "Angela (Theme from Taxi (1978))", was written/performed by Bob James and was from his 1978 album 'Touchdown'. The album's title track was the song James had actually written for the theme, but Taxi's producers liked the short cue Bob had recorded for one brief scene with Alex (Judd Hirsch) and a young woman, Angela, and used that instead.
The series was inspired by a 1975 article in New York magazine titled "Night-Shifting for the Hip Fleet" by Mark Jacobson. James L. Brooks and David Davis read the article which was about several drivers who worked the night shift for a New York cab company.
In the opening credits the cab is being driven across New York's Queensboro (59th Street) Bridge by Tony Danza. The buildings in the background keep reappearing in the same place. The segment was shot once in the middle of the 1.4-mile bridge and then repeated several times to run throughout the entire credits.
Andy Kaufman had invented the persona for his character in his comedy act prior to working on the show, including the famous line "tank-you-veddy-much". It was the show's writers that came up with the name of Latka Gravas. Kaufman created Latka's language, which he taught to Carol Kane for her role as Simka, by inviting her to dinner and refusing to let her speak English.