Taxi's Cast

Alex Rieger..........................Judd Hirsch
Bobby Wheeler....................Jeff Conaway [1]
Louie De Palma....................Danny DeVito
Elaine Nardo.........................Marilu Henner
Tony Banta............................Tony Danza
John Burns.............................Randall Carver [2]
Latka Gravas........................Andy Kaufman
Reverend Jim Ignatowski.....Christopher Lloyd [3]
Simka Gravas........................Carol Kane [4]

Notes

[1] Jeff Conaway left the show in 1981.
[2] Randall Carver was written out of the show after the first season.
[3] Christopher Lloyd joined Taxi at the beginning of the second season (episode #27). He had appeared on the show as a guest star in episode #8.
[4] Carol Cane joined the cast in 1981. She had appeared in a previous episode (#40) in 1980.

In addition to the "regulars" listed above, there were several actors who were featured in three or more episodes:

Jeff.....................................J. Allen Thomas
Zena...................................Rhea Perlman
Phyllis Rieger....................Louise Lasser
Jason Nardo......................David Mendenhall
Jennifer Nardo..................Melanie Gaffin
Tommy...............................T.J. Castronova

During its five year run, Taxi had its share of famous guest stars. Here's an incomplete list of them, including the episode in which they appeared:

Allyse Beasely (#94)
Eileen Brenan (#54)
Dr. Joyce Brothers (#87)
Ted Danson (#84)
Ruth Gordon (#11)
Tom Hanks (#89)
Penny Marshall (#101)
Martin Mull (#20)
Lassie (#44)
Dick Sargent (#93)
Tom Selleck (#22)
Martin Short (#71)
Wallace Shawn (#91, 111)
Herve Villechaize (#44)
Dee Wallace (#34)
George Wendt (#64)

Nepotism at times played a part in the casting of Taxi guest stars. The following relatives appeared on one or more shows:

Rhea Perlman (#25,36,47,72,100, Danny DeVito's wife)
Julia DeVito (#62, 74, Danny DeVito's mother)
Mark Anthony Danza (#24, 37, Tony Danza's son)
Michelle Conaway (#14, Jeff Conaway's sister)
Suzanne Carney (#17, Marilu Henner's niece)