(written from a Production point of view)
Jay D. Jones is an actor and stuntman who worked on several projects in the 1960s and 1970s including several episodes of Star Trek: The Original Series. He was also credited as Jimmy Jones sometimes in his career.
Jones was not familiar with the series at all when he got his first role in the series (as Crewman Jackson in "Catspaw"), and had to ask the neighbor's boy what his sole line ("I'm ready to beam up, sir") actually meant. He was hired for the episode because the role needed someone who could do his own stunt fall. After his first appearance, he was frequently called back to the series for smaller parts and stunt work, apparently because Gene Roddenberry took a liking to him. (These Are the Voyages: TOS Season Two, p. 43)
Jones filmed his scene for "Catspaw" on Tuesday 2 May 1967 at Desilu Stage 9, his scene for "Friday's Child" on Thursday 25 May 1967 on location at Vasquez Rocks, his scene for "Who Mourns for Adonais?" on Monday 5 June 1967 at Stage 10, and his scene for "The Changeling" on Friday 7 July 1967 at Stage 9. He filmed his scenes for "The Apple" between Monday 17 July 1967 and Wednesday 19 July 1967 at Stage 10, his scene for "Mirror, Mirror" on Thursday 27 July 1967 at Stage 9, and his scene for "The Trouble with Tribbles" on Tuesday 29 August 1967 at Stage 10. He filmed his scene for "A Private Little War" on Friday 6 October 1967 at Paramount Pictures' B Tank, his scene for "The Immunity Syndrome" on Monday 30 October 1967 at Stage 9, and his scenes for "A Piece of the Action" on Monday 6 November 1967 on location at Paramount's McFadden Street backlot.
Jones appeared in movies including the western Rough Night in Jericho (1967, starring Jean Simmons), the action film The Poseidon Adventure (1972, with Phil Adams, Bill Catching, Victor Paul, George Sawaya, and Paul Stader), and the drama The Men's Club (1986, with Frank Langella and Craig Wasson) on which he worked as stunt coordinator.
He also appeared in episodes of The Man from U.N.C.L.E. (1967, with Robert DoQui and Pete Kellett), The High Chaparral (1969, with Henry Darrow), Bonanza (1970-1972, with Robert Lansing, Alfred Ryder, Biff Manard, and Andrew J. Robinson), The F.B.I. (1972), and Kung Fu (1975, with David Huddleston, Keye Luke, Stephen Manley, and Lloyd Kino).
Jones threw the hatchet in the opening scene of the television series Dr. Quinn, Medicine Woman in 1993. In addition, he appeared in the Scorpions 1990 music video "Tease Me Please Me" as well various commercials.
In an interview for the book Science Fiction Television Series by Mark Phillips and Frank Garcia, Jones reveals that he had to be hospitalized twice for injuries suffered from his work on Star Trek. As James Doohan's stunt double in "Who Mourns for Adonais?" Jones suffered a concussion after hitting himself on the head following a back flip. And while playing the role of security guard Mallory on "The Apple", Jones was severely injured by the explosion which was supposed to kill his character.