Many cast and crew have worked on other important science fiction films and television. The following are probably the major science fiction series, with a simple guide to who to look out for.
- Star William Shatner's first acting job was in a Canadian theatre group headed by Barry Morse (Victor Bergman)
- Martin Landau (John Koenig) was considered for the role of Spock, but declined in order to do Mission: Impossible (shot on an adjacent stage to Star Trek at Paramount Studios).
- Joan Collins (Kara, Mission Of The Darians) was a guest star in the episode "City On The Edge Of Forever" (1967).
- Karl Held (Jerry Travis, The Immunity Syndrome) was a guest star in the episode "The Return Of The Archons" (1967, credited as Christopher Held). Thanks to Dana Lubich.
- Writer Art Wallace (Siren Planet) wrote the episodes "Obsession" (1967) and "Assignment Earth" (1968)
- Fred Freiberger (Year 2 producer/ writer) produced the third and final series of Star Trek (1969).
- Kathryn Leigh Scott (Yesta, Dorzak) was a guest star in Who Watches The Watchers, 1989
- Carolyn Seymour (Eva, Seance Spectre) was a guest star in Contagion, 1989, First Contact, 1991, Face Of The Enemy, 1993, and, in Star Trek Voyager, Eye Of The Needle, 1995, Cathexis, 1995, Persistence of Vision, 1995
- Jeremy Kemp (Queller, Voyager's Return) was a guest star in Family, 1990.
- Nick Tate (Alan Carter) was a guest star in the episode Final Mission (1990), and in the Star Trek Deep Space Nine episode Honour Among Thieves (1998). He was considered for the role of Quark in Deep Space Nine (1993).
Two British regional stations (including London) broadcast Space: 1999 at the same Saturday early evening slot as Doctor Who, then at the height of its success with Tom Baker as the Doctor. Inevitably Space: 1999 ratings were dented by the strong established competition, and in 1976 both stations shifted to different slots.
Among the regular cast, Prentis Hancock had several Who roles (London viewers could switch channels to see him playing spaceship controllers in both Moonbase Alpha and the four episodes of "Planet Of Evil" from 27 September 1975). Zienia Merton was in an early story. Two actors who played Doctor Who appeared in Space: 1999: Patrick Troughton and Peter Cushing.
- Dallas Adams (Sam, Lambda Factor) was a guest star in "Planet Of Fire", 1984.
- John Alkin (Andy Johnson, Mark Of Archanon) was a guest star in "Planet Of Fire", 1984
- Geoffrey Bayldon (Number 8, One Moment Of Humanity) was a guest star in Creature from the Pit, 1979
- Isla Blair (Female Alien, War Games and Carla, Journey To Where) was a guest star in King's Demons, 1983
- Brian Blessed (Rowland, Death's Other Dominion and Mentor, The Metamorph) was a guest star in Mindwarp (1986)
- Roy Boyd (Lustig, Immunity Syndrome) was a guest star in The Hand Of Fear, 1976
- Peter Brayham (Garth, Devil's Planet and Alphan in other episodes) was stunt coordinator for the episodes The Christmas Invasion (2005), New Earth (2006), and School Reunion (2006)
- Bernard Cribbins (Brian's voice, Brian The Brain) was in the film, Daleks Invasion Earth 2150 AD (1966), and a recurring character (Wilfred Mott) in several stories in the 2007-2010 seasons.
- Peter Cushing (Raan, Missing Link) played the Doctor in the film, Daleks Invasion Earth 2150 AD, 1966
- Andy Dempsey (operative, Year One) was a guest in The Time Monster, 1972 and The Face Of Evil, 1977
- Gregory De Polnay (Pete Garforth, Lambda Factor) was a guest star in The Robots Of Death, 1977
- Max Faulkner (Ted Clifford, Ring Around The Moon) was a guest star in The Monster of Peladon, 1974, Planet Of The Spiders, 1974, Android Invasion, 1975, The Invasion of Time, 1978,
- Harry Fielder (George, Seance Spectre, also in Lambda Factor, Immunity Syndrome and The Dorcons) was an extra in The Wheel in Space (1968), Planet of the Spiders (1974), Revenge of the Cybermen (1975), The Seeds of Doom (1976), The Deadly Assassin (1976), The Face of Evil (1977), The Invisible Enemy (1977), The Ribos Operation (1978) , The Armageddon Factor (1979), Meglos (1980), Castrovalva (1982)
- Julian Glover (Jarak, Alpha Child) was a guest star in The Crusades (1969), and City Of Death (1979).
- Guy Francois Groen (Technician, Black Sun, Earthbound) was an extra in Arc of Infinity (1983).
- John Hamill (Dominix, Force of Life) was a guest star in The Ribos Operation, 1978.
- Prentis Hancock (Paul Morrow) was a guest star in "Spearhead From Space", 1970, "Planet Of The Daleks", 1973, "Planet Of Evil", 1975, and "The Ribos Operation", 1978
- Laurence Harrington (Jackson in Journey to Where, Stewart in The Dorcons) was in The Mind of Evil, 1971, and in Frontier in Space, 1973
- Alan Harris (Alphan, many Year 1 episodes) was a guest star in Face Of Evil, 1963
- Joy Harrison (Main Mission operative in Earthbound, Another Time, Another Place) was in Death to the Daleks, 1974
- Nick Hobbs (Clive Kander, Bringers Of Wonder) was in Mind Of Evil, 1971, The Curse of Peladon, 1972, The Time Monster (1972), and the Monster Of Peladon, 1974, The Ark in Space (1975)
- Gareth Hunt (pilot, Guardian Of Piri) was a guest star in Planet Of The Spiders, 1974
- Godfrey James (Alien Transport, Rules Of Luton) was a guest star in Underworld, 1978
- Paul Jerrico (Security guard, Dorzak) was a guest star in Arc Of Infinity, 1983
- Alf Joint (Steiner, Breakaway and Overseer, The Metamorph) was a stuntman on many episodes.
- Bernard Kay (mutant, New Adam new Eve) was a guest star in Dalek Invasion of Earth, 1964, The Crusades, 1965, The Faceless Ones, 1967, Colony In Space, 1971
- Gypsie Kemp (Earth nurse, Dragon's Domain) was a guest star in Day of the Daleks (1972).
- Annie Lambert (operative, various episodes) was a guest star in Four To Doomsday 1981
- John Laurimore (Smitty, Black Sun) was a guest star in Masque of Mandragora 1976
- Philip Madoc (Gorski, Breakaway) was a guest star in War Games, 1969, The Krotons, 1969, Brain of Morbius (1976), The Power Of Kroll, 1978, The Eleventh Hour, 2010.
- Roy Marsden (Crael, Devil's Planet) was a guest in Smith and Jones (2007).
- Zienia Merton (Sandra) was a guest star in the story Marco Polo, 1964, and in the spin-off series The Sarah Jane Adventures, story The Wedding of Sarah Jane Smith, 2009.
- Stuart Myers (Alphan, various episodes) played a a technician in Doctor Who and the Silurians 1970, an Axon blob in The Claws of Axos 1971, and Draconian in Frontier in Space 1973
- Tony Osoba (security guard, Space Warp) was a guest star in Destiny Of The Daleks, 1979 and Dragonfire, 1987, and Kill The Moon, 2014.
- Alibe Parsons (Alibe) was a guest star in "Mindwarp", 1986.
- Brendan Price (security guard, Catacombs Of The Moon) was a guest star in Face Of Evil, 1977
- Robert Russell (Hadin, Mission Of The Darians) was a guest star in Terror of the Zygons, 1975
- John Sarbutt (frozen guard, Force Of Life) was a guest star in Genesis of the Daleks (1975) and Four To Doomsday (1982)
- Catherine Schell (Maya) was a guest star in the episode City Of Death, 1979
- Robin Scott (Eric Sparkman, Breakaway) was a guest star in The Moonbase (1967), The Krotons (1969), and The War Games (1969).
- Michael Sheard (Dr Darwin King, Dragon's Domain) was a guest star in The Ark, 1966, Mind Of Evil, 1971, Pyramids Of Mars, 1975, the Invisible Enemy, 1977, Castrovalva, 1981, Remembrance Of The Daleks, 1988
- Roy Stewart (alien, The Metamorph) was a guest star in Tomb Of The Cyberman, 1967, and Terror Of The Autons, 1971
- Kevin Stoney (Talos, Last Enemy) was a guest star in The Dalek Master Plan, 1966, The Invasion 1968 and Revenge Of The Cybermen, 1975
- Barry Summerford (prisoner, Devil's Planet) was in Invasion of the Dinosaurs part 6 (1974), Robot (1974), Genesis of the Daleks (1974), Terror of the Zygons (1975), The Seeds of Doom (1976), The Hand of Fear (1976), The Sun Makers (1977), The Ribos Operation (1978), The Creature from the Pit (1979), Shada (unaired, 1979), The Keeper of Traken (1981)
- Patrick Troughton (Archon, The Dorcons) was the second actor to play the Doctor, 1966-1969, reprised in 1973 and 1984
- Kelly Varney (Superswift crew, Bringers Of Wonder part 1) was in Planet of the Daleks (1973), Invasion of the Dinosaurs (1974), The Sun Makers (1977)
- Terry Walsh (rescue Eagle pilot, Mark Of Archanon, and Scotsman, Journey To Where) was a stuntman in numerous episodes, 1968-1979
- Jeremy Young (Jack Bartlett, Bringers Of Wonder) was a guest star in An Unearthly Child, 1963 and Mission To The Unknown, 1965
- Nik Zaran (Jackson, Breakaway) was a guest star in The Space Pirates, 1969
- Johnny Byrne (writer) wrote the episodes The Keeper Of Traken, 1981, Arc Of Infinity, 1983, Warriors Of The Deep, 1984. In 1980 he was considered by the BBC to replace Douglas Adams as script editor for Tom Baker's final series in the show (the job went to Christopher Bidmead).
- Pip and Jane Baker (writers, A Matter Of Balance) wrote the episodes Mark Of The Rani, 1985, Trail Of A Time Lord part 3, 1986, Time & The Rani, 1987
- Terence Dicks (writer, The Lambda Factor) was script editor from 1968-1974 and wrote many episodes.
- Dennis Spooner (writer, Alien Attack scenes) was script editor from 1964-1965
- Martin Bower (model-maker) made models for the series including Pirate Planet (1978), Earthshock (1982), Vengeance on Varos (1985). He built a Tardis model used from 1982 onwards.
- Nick Allder (SFX lighting cameraman) filmed SFX sequences for The Space Pirates (1969), and The Invisible Enemy (1977). In the later episode, filmed at Bray Studios, he used the "barrel moon" model from Space: 1999 (see more).
The first live action science fiction series by Gerry Anderson. Space: 1999 was originally conceived as a the second series of UFO
- Patrick Allen (Chairman, Alien Attack) played Turner in Timelash.
- John Clifford (Guard, The Dorcons) was a Shado operative in most episodes.
- Maxwell Craig (Guard, The Dorcons) was a Shado operative and an alien.
- Stuart Damon (Parks in Matter of Life and Death, Guido in Bringers of Wonder) played Howard Byrne in Mindbender.
- Alan Harris (Alphan in many episodes) was SkyDiver operative in Destruction
- Anouska Hempel (Annette Fraser in Metamorph) played the Shado radio operator in The Man Who Came Back, Reflections In The Water, Mindbender, The Long Sleep.
- Drewe Henley (Ehrlich in Bringers of Wonder) played Captain Steve Maddox in Conflict.
- Godfrey James (Alien Transport in Rules of Luton) played Game Warden Mitchell in The Square Triangle.
- Susan Jameson (Prof. Juliet Mackie in Dragon's Domain) played Anne Stone in The Sound Of Silence.
- Philip Madoc (Commander Gorski in Breakaway) played Steven Rutland in A Question Of Priorities and Captain Steven in Destruction.
- Patrick Mower (Reilly in All That Glisters) played Cass Fowler in The Square Triangle
- Diana Reeves (Technician, nurse in The Troubled Spirit and Space Brain) was a Shado operative in Court Martial.
- Shane Rimmer (Kelly, Space Brain) played Bill Johnson in Identified and Computer Affair, and CIA agent in Confetti Check A-O.K..
- Barry Stokes (Jim Haines in Voyager's Return) played a Skydiver Engineer in Destruction and Reflections In The Water.
- Maureen Tann (Nurse/ Main Mission Operative in Force Of Life, Alpha Child, The Last Sunset) played a Moonbase operative in Reflections In The Water
- Douglas Wilmer (Commissioner Dixon in Dragon's Domain) played Dr Brunner in E.S.P.
Connections