(written from a Production point of view)
John Arndt (17 November 1928 – 16 December 2021; age 93) was an actor who has made five appearances in Star Trek: The Original Series. Since his first character, Sturgeon, died in his appearance, subsequent appearances by Arndt are referenced to the second character he played, Fields.
He filmed his scenes for "Balance of Terror" on Monday 25 July 1966 at Desilu Stage 9 and his scenes for "Dagger of the Mind" on Thursday 11 August 1966, also at Stage 9. He filmed his scenes for "Miri" on Monday 22 August 1966 and Wednesday 24 August 1966 at Stage 10 and on location at the 40 Acres backlot.
Arndt was the assistant basketball coach for Loyola Marymount University's 1960-61 NCAA Division 1 league championship team, and the following 1961-62 season became the University's head basketball coach and athletic director through 1967-68. During that period, the team had 91 career victories, making him the Lion's second all-time winningest coach; he was inducted into their Hall of Fame in 1986. Arndt, himself, was a 1952 graduate of Loyola Marymount, played during the 1949-50 basketball season, and considered to be one of the team's classiest ball handlers.  Followed by a short career as a star player in the NIBL pro-team, the Los Angeles Fibber McGee & Mollys for the 1951 and 1952 seasons, and the Los Alamitos Flyers during the 1953 season.  During the early 50s, Arndt also served in the US Naval Reserve. 
Between his coaching duties, Arndt had several uncredited or minor television roles in 1966 and 1967, including the portrayal of "wild Indians on TV", which, along with his appearances on Star Trek, he also picked up three appearances on Mission: Impossible, in episodes featuring Nick Borgani, Antoinette Bower, Dave Cadiente, Sid Haig, Bob Johnson, Percy Rodriguez, Joseph Ruskin, George Sawaya, Warren Stevens, Michael Strong.
From the mid-70s to mid-90s, Arndt sporadically appeared in a dozen other television series or films, where in addition to "Miri", "Dagger of the Mind" and "Balance of Terror", he appeared in an inordinate number of Vincent McEveety directed presentations, including: Gunsmoke (1975, with Ed McCready), Kolchak: The Night Stalker (1975, with Paul Baxley and Ed McCready), Gus (1976, with David Armstrong, Peter Paul Eastman, Mel Gold, Monty O'Grady, Al Roberts, and Vic Toyota), The Apple Dumpling Gang Rides Again (1979, with Lou Elias, Kenneth Mars, Robert Pine, Nick Ramus, Ed McCready, and Vince Deadrick, Jr., Amy (1981, with Seamon Glass), and finally, an episode of Diagnosis Murder (1994).
Between 1984 and 1996, Arndt worked as stand-in on the television series Murder, She Wrote and also appeared in front of the camera in at least two episodes where he worked with Ronnie Claire Edwards, Cyril O'Reilly, James Sloyan, and Hallie Todd.
In addition to "The Man Trap" and "Space Seed", Arndt's "non-McEveety" appearances included the film The Deadly Spawn (1983), one more episode of Murder, She Wrote (1985, with Joey Banks), and two episodes of The New Leave It to Beaver (1988-89).
Arndt died on 16 December 2021 at the age of 93 at his home in Huntington Beach, California. (Los Angeles Times, 28 December 2021)
Star Trek appearances
- As Sturgeon
- As Fields