Steve Ihnat Steve Ihnat ( born Stefan Ihnat ) was the actor , writer , and director who played the legendary Fleet Captain Garth of Izar in the episode . He filmed his scenes between Tuesday and Tuesday at Desilu Stage 9 and Stage 10 . He was born in Czechoslovakia but immigrated to Canada with his family when he was five years old . In the 1950s , he moved to the United States to pursue an acting career . On television , Ihnat guest - starred on several episodes of " Bonanza " , " Gunsmoke " , " Mission : Impossible " , " Mannix " , and " The F . B . I . " , the latter of which starred fellow TOS guest performer Stephen Brooks . One of Ihnat ' s later appearances on " The F . B . I . " ( after Brooks left the show ) featured several other TOS guest stars : Paul Carr , Clint Howard , Richard Evans and Paul Fix . In 1963 , Ihnat guest - starred on the western television series " Temple Houston " , which starred Jeffrey Hunter in the title role . Ihnat again worked with Hunter on the 1965 film " Brainstorm " . Ihnat worked frequently with director James Goldstone between 1964 and 1966 . Their first collaboration was an episode of " Voyage to the Bottom of the Sea " , along with Jill Ireland and David Opatoshu . This was followed by a two - parter of " The Outer Limits " and episodes of " The Fugitive " , " Rawhide " ( with John Anderson ) , " Perry Mason " , " Blue Light " , and " The Iron Horse " . On the latter , Ihnat again worked with TOS regular James Doohan . In 1965 , Ihnat was the star of an unsold pilot called " Police Story " , written by " Star Trek " creator Gene Roddenberry . TOS stars DeForest Kelley and Grace Lee Whitney had supporting roles in this pilot , as did TOS guest star Malachi Throne . The pilot was eventually aired in 1967 . Ihnat has also made appearances in a handful of films . One of his earliest films was one which he co - wrote , a 1963 drama entitled " Strike Me Deadly " . He later had a supporting role in the 1966 drama " The Chase " , which was followed by a role in the 1967 spy comedy " In Like Flint " . In the latter , he worked for the first time with his " Whom Gods Destroy " co - star Yvonne Craig . Ihnat next played Andy Warshaw in the 1967 western film " Hour of the Gun " , working alongside William Windom , William Schallert , Monte Markham , Robert Phillips and Dave Perna ; the film featured music by Jerry Goldsmith . Ihnat then had a role in Robert Altman ' s 1968 science fiction film " Countdown " , which featured music by Leonard Rosenman , which was followed by the crime drama " Madigan " that same year . The latter also starred fellow " Trek " alumni Michael Dunn , Lloyd Haynes , and Gloria Calomee . After working with director Richard Colla on the 1969 TV movie " The Whole World Is Watching " , Ihnat and Colla reteamed for two feature films : " Zigzag " ( 1970 ) and " Fuzz " ( 1972 ) . Both of these films co - starred Stewart Moss ; the former also featured William Marshall and Vic Perrin . " Fuzz " would prove to be Ihnat ' s last feature film appearance . Ihnat also wrote and directed a pair of films , 1970 ' s " Do Not Throw Cushions Into the Ring " and 1972 ' s " The Honkers " . He starred in the former film along with Sally Carter , whom he married on 23 May 1970 . A heart attack claimed Steve Ihnat ' s life in 1972 . He was only 37 years old . He was attending the Cannes film festival promoting " The Honkers " when he died . He was survived by his wife of nearly two years , Sally , and their two children . Ihnat ' s final work was a leading role in " Hunter " , a TV movie thriller which co - starred Bill Erwin , Sabrina Scharf , John Schuck , Fritz Weaver , and Jason Wingreen . This movie aired on CBS in January 1973 , nearly eight months after Ihnat ' s death .