Bill Mumy Charles William " Bill " Mumy Jr . , sometimes credited as Billy Mumy , is an actor from San Gabriel , California , who played Crewman in the episode . Mumy had wanted to appear on the show for some time prior to this episode but he only wanted to play a Human , as he had worn alien makeup for years as a cast member of " Babylon 5 " . ( " " ) Mumy is perhaps best known for his childhood role as young Will Robinson on the classic science fiction series from 1965 through 1968 . Other " Trek " alumni he worked with during the show are Keith Taylor , Michael J . Pollard , Michael Ansara , Torin Thatcher , Liam Sullivan , Sherry Jackson , Peter Brocco , Ted Cassidy , Malachi Throne , John Abbott , Ron Gans , Arthur Batanides , Bart La Rue , Lou Wagner , Don Eitner , John Crawford , Byron Morrow , Abraham Sofaer , Stanley Adams , writers Shimon Wincelberg , Carey Wilber and Robert Hamner , directors Alexander Singer , Tony Leader , and Leo Penn , and composers Alexander Courage , Gerald Fried , and Fred Steiner . By the time he took on that role , however , he had already been acting in television and films for five years , having joined show business at his own insistence – at the age of five . Prior to " Lost in Space " , Mumy appeared on such classic shows as " Alfred Hitchcock Presents " , " Wagon Train " , " Perry Mason " , " The Fugitive " ( in an episode with Andrew Prine , Clint Howard , and James B . Sikking ) , " The Munsters " , " Bewitched " , and several episodes of , most notably 1961 ' s " It ' s a Good Life " ( which co - starred Don Keefer and was written by Jerome Bixby ) . In addition , he made appearances in films like 1963 ' s " A Child Is Waiting " ( co - starring Lawrence Tierney ) and " Palm Springs Weekend " and 1965 ' s " Dear Brigitte " . Following the cancellation of " Lost in Space " in 1968 , Mumy starred in the 1969 Walt Disney film " Rascal " , which also featured guest actor John Fiedler . In 1971 , he starred in Stanley Kramer ' s drama " Bless the Beasts & Children " , and in 1973 , he had a supporting role in the classic biographical film " Papillon " . This latter film co - starred fellow " Star Trek " alumni Peter Brocco , Gregory Sierra , William Smithers , Ron Soble , Vic Tayback , and Anthony Zerbe . Also in 1973 , Mumy portrayed the role of Weaver in the TV movie " Sunshine " , starring Cliff DeYoung and Meg Foster , also featuring Noble Willingham , and directed by Joseph Sargent . Mumy , Foster , and De Young would go on to reprise their roles in a short - lived 1975 series also entitled " Sunshine " and a 1977 TV movie follow - up , " Sunshine Christmas " . Besides these , Mumy ' s only other TV credits during the 1970s were two episodes of " The Rockford Files " , including the pilot . Mumy did very little in film or television during the 1980s . His only notable credits during this time was an appearance in " Twilight Zone : The Movie " ( in a segment remaking the aforementioned " It ' s a Good Life " episode , with Mumy in a different role , and co - starring Dick Miller and William Schallert , while John Larroquette , Peter Brocco and Bill Quinn also appeared in the movie in another segments ) and a guest spot on " Matlock " ( in an episode with Michael Durrell , Lawrence Pressman , and Carolyn Seymour ) . His career picked up some speed in the early 1990s with roles in the films " Captain America " ( 1990 , which also featured Ronny Cox and Michael Nouri ) and " Double Trouble " ( 1992 , co - starring James Doohan ) and appearances on " The Flash " and " Superboy " . In 1994 , Mumy began starring in " Babylon 5 " , playing the role of . Other " Bablyon 5 " regulars and semi - regulars to have appeared on " Star Trek " include Walter Koenig , Andreas Katsulas , Caitlin Brown , Mary Kay Adams , Robert Rusler , Patricia Tallman , Tracy Scoggins , John Vickery , Marshall Teague , John Schuck , Robin Sachs , Rick Scarry , Anthony De Longis , Patrick Kilpatrick , and Reiner Schöne . In 1996 , he and Peter David co - created the short lived science fiction series " Space Cases " for the children ' s cable channel Nickelodeon . George Takei appeared in several episodes as a recurring villain . After " Babylon 5 " ended in 1998 , and after he appeared on " Deep Space Nine " , Mumy went on to reprise his role as the supernatural Anthony Fremont from the " It ' s a Good Life " episode of " The Twilight Zone " in a follow - up story for UPN ' s 2002 - 03 version of " Twilight Zone " entitled " It ' s Still a Good Life " , written by Ira Steven Behr . In 2006 , he co - starred with " Trek " regulars Michael Dorn , Robert Picardo , and George Takei in the TV movie " Shockwave " ( aka " A . I . Assault " ) . Additionally , Mumy continues to expand his credits in the field of voice acting , having lent his voice to a number of animated TV programs and direct - to - video films , including an episode of " Batman : The Animated Series " , co - starring Loren Lester . Mumy is also a musician and is one - half of the popular " novelty rock " duo along with childhood friend Robert Haimer . The duo is perhaps most famous for their song " Fish Heads " . He and Haimer co - wrote and starred in an animated short based on this song in 1982 . Before his appearance on " Deep Space Nine " , Mumy had worked in " Star Trek " on one previous occasion : he co - wrote ( with [ [ Peter David ] ] ) three issues of the [ [ DC TOS volume 2 ] ] series of [ [ comics ] ] . The story depicted the " Enterprise " - A ' s encounter with The Worthy , a group of alien characters modeled after the cast of " Lost in Space " , who had , predictably enough , been lost in space for centuries . External links . [ [ de : Bill Mumy ] ] [ [ es : Bill Mumy ] ] [ [ nl : Bill Mumy ] ] [ [ Category : DS9 performers ] ] [ [ Category : Star Trek comic authors ] ]