(written from a Production point of view)
The following is a list of characters who appeared first in one television or film series, and subsequently appeared in a different television or film series. (Appearances by TOS characters in the TOS films, or TNG characters in the TNG films, are not listed.)
Star Trek: The Original Series
- James T. Kirk
- Christopher Pike (played by Anson Mount, originally played by Jeffrey Hunter and Sean Kenney)
- Spock (as played by Leonard Nimoy)
- Spock (played by Ethan Peck)
- Leonard McCoy
- Montgomery Scott
- Pavel Chekov
- Zefram Cochrane (played by James Cromwell, originally played by Glenn Corbett)
- Amanda Grayson (originally played by Jane Wyatt)
- Kahless the Unforgettable (played by Kevin Conway, originally played by Robert Herron)
- Harry Mudd (played by Roger C. Carmel)
- Stella Mudd (played by Katherine Barrell, originally played by Kay Elliot)
- Sarek (played by Mark Lenard)
- Surak (played by Bruce Gray, originally played by Barry Atwater)
- T'Pau (played by Kara Zediker and an uncredited Betty Matsushita, originally played by Celia Lovsky)
- Una (played by Rebecca Romijn, originally played by Majel Barrett-Roddenberry)
- Bob Wesley (voiced by James Doohan, originally played by Barry Russo)
The Original Series films
Star Trek: The Next Generation
- Reginald Barclay
- Keiko O'Brien
- "A Man Alone"
- "If Wishes Were Horses"
- "In the Hands of the Prophets"
- "The Siege"
- "Armageddon Game"
- "The House of Quark"
- "Hard Time"
- "Body Parts"
- "Looking for par'Mach in All the Wrong Places"
- "The Assignment"
- "The Begotten"
- "Time's Orphan"
- "What You Leave Behind"
- Miles O'Brien
- Molly O'Brien
- Alexander Rozhenko
The Next Generation films
- Borg Queen
Star Trek: Deep Space Nine
Star Trek: Voyager
Star Trek: Discovery
Star Trek: Short Treks
- Leonardo da Vinci
- No characters who first appeared on Star Trek: The Animated Series or Star Trek: Enterprise have recurred in a subsequent series or film.