Gary Lockwood Gary Lockwood is the actor who played Lieutenant Commander Gary Mitchell in the second pilot for , called . He filmed his scenes between Monday and Wednesday at Desilu Culver Stage 15 , Stage 16 , and Stage 17 , participating in all eight days of production . Lockwood is perhaps best known for his role as Dr . Frank Poole in the revered 1968 science fiction film . Despite his one - time guest appearance in the " Trek " franchise , Lockwood participated in the 1997 documentary " Trekkies " , which chronicles the impact of " Star Trek " on the US culture . Early years . Lockwood was born John Gary Yurosek in Van Nuys , California and attended the University of California at Los Angeles ( UCLA ) on a football scholarship . He broke into show business as a stuntman and as a stand - in for actor Anthony Perkins in 1957 , but he quickly moved to acting . His first movie as an actor was the 1959 western " Warlock " , which also featured fellow " Star Trek " alumni Whit Bissell , Paul Comi , Frank Gorshin , Roy Jenson , and DeForest Kelley . That same year , Lockwood made his major television acting debut on an episode of " Bronco " , alongside Yvonne Craig . Lockwood made an uncredited appearance in the 1960 film " Tall Story " , which starred later and guest actor , Ray Walston . Lockwood ' s first credited film role came a year later in the Elvis Presley picture " Wild in the Country " ; he again worked with Presley ( and Yvonne Craig ) in 1963 ' s " It Happened at the World ' s Fair " . Pete Kellett , Bill Quinn and Guy Raymond also appeared in the latter film . Lockwood ' s early feature film credits also included the Academy Award - winning 1961 drama " Splendor in the Grass " and 1962 ' s " The Magic Sword " ( which co - starred Liam Sullivan ) . From 1963 through 1964 , Lockwood was the star of the television series called " The Lieutenant " , a show which , like " Star Trek " , was created by Gene Roddenberry . Many other performers who later worked on " Star Trek " appeared in this series , including TOS regulars Walter Koenig , Nichelle Nichols , and Leonard Nimoy , recurring " Trek " actress Majel Barrett , and such guest performers as Barbara Babcock , James Gregory , Paul Lambert , Don Marshall , Oliver McGowan , Dallas Mitchell , Ricardo Montalban , William O ' Connell , Leslie Parrish , Andrew Prine , Madlyn Rhue , Michael Strong , and Kenneth Tobey . Many episodes of " The Lieutenant " were directed by Vincent McEveety . McEveety later directed Lockwood in a two - part episode of " Gunsmoke " which aired in early 1965 and in the 1968 western film " Firecreek " . The latter also featured fellow TOS guest stars Barbara Luna and Morgan Woodward and TNG guest star Brooke Bundy . Besides this , Robert Butler and David Alexander both directed two episodes of " The Lieutenant " . Lockwood ' s early television credits also included a guest spot on the NBC drama " Saints and Sinners " , under the direction of veteran TOS director Marc Daniels . Lockwood then appeared in an episode of " Perry Mason " with Anthony Caruso , followed by an episode of " Combat ! " with Jim Goodwin . In 1964 , Lockwood made a guest appearance on " 12 O ' Clock High " , a series which starred TOS guest actors Robert Lansing and Frank Overton . He reprised his role from this episode the following year , then made a third appearance on the show in a different role . Nancy Kovack was also seen in Lockwood ' s first episode ; Lee Meriwether appeared in the third . In 1965 , Lockwood acted alongside Sally Kellerman on an episode of the Canadian series " Seaway " and in a segment of " Kraft Suspense Theatre " entitled " Connery ' s Hands " ( the latter also featured Francine Pyne ) . Lockwood and Kellerman later worked opposite each other on " Where No Man Has Gone Before " the same year . Later career . Following his iconic role in " 2001 : A Space Odyssey " , Lockwood has only acted in a handful of films . He acted alongside Graham Jarvis , Don Keefer , John McLiam , and Paul Winfield in the 1970 Stanley Kramer drama " R . P . M . " , which was followed in 1972 by the comedy " Stand Up and Be Counted " , which co - starred Michael Ansara and the aforementioned Madlyn Rhue . He then starred in a number of low - budget independent films , including " Project : Kill " ( 1976 ) , " Survival Zone " ( 1983 ) , and " Night of the Scarecrow " ( 1995 , with Stephen Root ) . The majority of Lockwood ' s career since the 1970s has been comprised of television guest appearances , made - for - TV movies , and other television projects . In 1971 , he starred in " Earth II " , an unsold pilot for a proposed science fiction television series . Mariette Hartley starred in this production , as well . Lockwood also worked on the pilot for the short - lived series " The Manhunter " , along with John Anderson , Lenore Kasdorf , and Tim O ' Connor . Among the television shows on which Lockwood guest - starred throughout the 1970s are " Medical Center " ( with Barbara Baldavin and series regular James Daly ) , " Mission : Impossible " ( with Jason Evers ) , " Ironside " ( again working with Madlyn Rhue ) , " The Six Million Dollar Man " ( two episodes : one with William Schallert , the other directed by Russ Mayberry ) , " The Bionic Woman " ( with Jeff Corey ) , and " Starsky and Hutch " ( which starred David Soul as " Hutch " ) . Lockwood also made numerous appearances on the drama series " Barnaby Jones " , each time playing a different character . Aforementioned TOS guest star Lee Meriwether was a regular on this series ; others Lockwood worked with on the show include Ward Costello , Meg Foster , Ellen Geer , Vince Howard , William Lucking , Phillip Pine , Lawrence Pressman , the aforementioned Michael Strong , and director Corey Allen . In the mid - 1980s , Lockwood reunited with his " Star Trek " co - star William Shatner for two episode of " T . J . Hooker " , the police drama on which the Kirk actor played the title role . James Darren ( later of ) was also a regular cast member at the time . Lockwood ' s first episode ( " The Snow Game " , 1984 ) was directed by Shatner himself , while the second episode ( " To Kill a Cop " , 1985 ) guest - starred Julie Cobb and Thalmus Rasulala . Lockwood made four appearances each on the TV dramas " Simon & Simon " and " Murder , She Wrote " , portraying a different character in each episode . Veteran " Star Trek " director Vincent McEveety , whom Lockwood worked with many times during the 1960s , directed Lockwood in one episode from each series . On " Simon & Simon " , he also worked with fellow " Trek " performers Daphne Ashbrook , Michael Dante , and Kenneth Mars ; on " Murder , She Wrote " , he acted with Theodore Bikel , Joanna Cassidy , Mary Crosby , Allan Miller , Robert O ' Reilly , and William Windom . Throughout the 1980s , Lockwood has also made guest appearances on such programs as " Charlie ' s Angels " ( directed by Kim Manners ) , " Hart to Hart " ( with Andrew Robinson ) , and " MacGyver " ( with Bruce McGill ) . He also continued appearing in TV movies , including the 1983 drama " Emergency Room " , in which he worked with " Next Generation " regular LeVar Burton as well as Warren Munson , John Vargas , Gary Faga , Biff Yeager , Michael Spound , and Gary Frank . He also had a supporting role in 1987 ' s " The Return of the Six - Million - Dollar Man and the Bionic Woman " along with William Campbell and Tom Schanley . Lockwood ' s most recent television work was a guest spot on the science fiction series " Dark Skies " in 1997 . Jeri Ryan , who later joined the cast of " Star Trek : Voyager " , was a regular on this series at the time . The episode in question , " The Warren Omission " , also guest - starred Dennis Creaghan and Conor O ' Farrell . Additional credits . Other film and television projects not mentioned above in which Lockwood worked with other " Star Trek " alumni include :