<Ul> <Li> Dr. ( Professor ) John Robinson ( Guy Williams ) : The expedition commander and the father of the Robinson children . He is an astrophysicist who also specializes in applied planetary geology . </Li> <Li> Dr. Maureen Robinson ( June Lockhart ) : John 's biochemist wife . Her role in the series is often to prepare meals , tend the garden , and help with light construction while adding a voice of compassion . Her counsel is sometimes the only thing that prevents the Robinsons from leaving Dr. Smith behind after some of his particularly heinous actions , because she finds it unthinkable to condemn any human being to a life of total isolation from his own kind . Her status as a doctor is mentioned only in the first episode and in the second - season episode `` The Astral Traveler '' . </Li> <Li> Major Don West ( Mark Goddard ) : The military pilot of the Jupiter 2 . He is Dr. Smith 's intemperate and intolerant adversary . His mutual romantic interest with Judy was not developed beyond the first few episodes . In the un-aired pilot , `` Doctor Donald West '' was a graduate student astrophysicist and expert in interplanetary geology , rather than a military man . </Li> <Li> Judy Robinson ( Marta Kristen ) : The oldest child of the Robinsons . She is about 19 years old at the outset of the series . In the unaired pilot , she is described as having given up a promising career in musical theater to go with her family instead . </Li> <Li> Penny Robinson ( Angela Cartwright ) : The middle child . An imaginative 11 - year - old in the first season , she loves animals and classical music . Early in the series , she acquires a chimpanzee - like alien pet with pointy ears that made one sound , `` Bloop '' . While it is usually referred to by Will and Professor Robinson as the bloop , Penny named the creature `` Debbie '' . Most of Penny 's adventures have a fairy - tale quality , underscoring her innocence . She is described in the unaired pilot , `` No Place To Hide '' , as having an IQ of 147 and an interest in zoology . </Li> <Li> Will Robinson ( Billy Mumy ) : The youngest child . A precocious 9 - year - old in the first season , he is a child prodigy in electronics and computer technology . Often , he is a friend to Smith when no one else is . Will is also the member of the family closest to the Robot . </Li> <Li> Dr. Zachary Smith ( Jonathan Harris ) : Acting as Alpha Control 's flight surgeon in the first episode , he is later referred to as a Doctor of Intergalactic Environmental Psychology , expert in cybernetics , and an enemy agent ( roles that are rarely mentioned after the initial episodes ) . His attempt to sabotage the mission strands him aboard the Jupiter 2 and results in its becoming lost . </Li> <Li> The Robot : The Robot is a Class M - 3 , Model B9 , General Utility Non-Theorizing Environmental Robot ( G.U.N.T.E.R. ) , which had no given name . Although a machine , endowed with superhuman strength and futuristic weaponry , it often displayed human characteristics , such as laughter , sadness , and mockery , as well as singing and playing a guitar . The Robot was performed by Bob May in a prop costume built by Bob Stewart . The voice was dubbed by Dick Tufeld , who was also the series ' narrator . The Robot was designed by Robert Kinoshita , who was also the designer of the iconic Robby the Robot for the 1956 sci - fi movie Forbidden Planet who made extensive appearances in subsequent films and productions . </Li> </Ul>
original cast of lost in space tv series
Guy Williams June Lockhart Mark Goddard Marta Kristen Angela Cartwright Billy Mumy Jonathan Harris Dick Tufeld