(written from a Production point of view)
William Morgan Sheppard (24 August 1932 – 7 January 2019; age 86), sometimes credited as W. Morgan Sheppard, was a British actor who played four characters throughout the Star Trek franchise. His last Star Trek appearance was as the head minister of the Vulcan Science Council in Star Trek.   He did not receive screen credit for his work on the latter. A picture of him was used for card #74, Vulcan Minister Orsak, of the 2013 virtual collectible card battle game Star Trek: Rivals.
While doing Additional Dialogue Recording for Star Trek, he told the film's director and producer J.J. Abrams – not realizing who he was speaking to – that the director was a "slave driver." He apologized after Abrams revealed himself to be the director. (Star Trek DVD commentary)
Outside of Star Trek, Sheppard is perhaps best known for his role as Blank Reg on the television series Max Headroom, which starred fellow Star Trek: The Next Generation guest actor Matt Frewer in the title role. He is also known for his portrayal of Confederate General Isaac Trimble in the films Gettysburg (for which he also provided, in his normal English accent, the opening narration describing the prelude to the battle) and Gods and Generals, both of which co-starred Billy Campbell, Joseph Fuqua, Kevin Conway, and Andrew Prine.
Born in London, England, and educated in Ireland, Sheppard graduated from London's Royal Academy of Dramatic Art in 1958. He then spent twelve years as Associate Artist with the Royal Shakespeare Company. He is the father of fellow Star Trek: Voyager guest actor Mark A. Sheppard, born in 1964. The two co-starred together in a number of productions, most notably Doctor Who and NCIS; in both cases, they played the same character at different ages.
In 1965, Sheppard began appearing in the original, Tony Award-winning Broadway production of The Persecution and Assassination of Marat as Performed by the Inmates of the Asylum of Charenton Under the Direction of the Marquis de Sade, which ran for 145 performances from December 1965 through April 1966.  Sheppard also appeared in the 1967 British film adaptation of the play.
In 1974, Sheppard appeared with future TNG co-star Patrick Stewart in a Royal Shakespeare Company production of Antony and Cleopatra. The production was video-taped and aired on US television in January 1975. Sheppard and Stewart worked together again on the films The Doctor and the Devils (1985) and Lady Jane (1986) before reuniting for the TNG episode "The Schizoid Man".
Throughout the 1970s and 1980s, he appeared on numerous British (and later American) television programs, mini-series and movies. Some of his credits during this time include The Professionals, The Duellists (1977, starring Keith Carradine), Hawk the Slayer (1980), The Sea Wolves (1980), The Elephant Man (1980), The Keep (1983), Max Headroom - 20 minutes into the future (1984, co-starring Matt Frewer), Lassiter (1984, co-starring Ed Lauter), Cry Freedom (1987, featuring Nick Tate), and Lucky Stiff (1988, co-starring Larry Cedar, Jeff Kober, Leigh J. McCloskey, and Bill Quinn). He also starred in the 1988 cult favorite, Elvira, Mistress of the Dark.
In the early 1990s, Sheppard had supporting roles in films such as David Lynch's Wild at Heart (1990), the 1992 comedy There Goes the Neighborhood (with DS9 guest stars Ron Taylor, Jonathan Banks, Harris Yulin, and Lee Arenberg), and the 1993 Stephen King horror film Needful Things (also featuring Star Trek VI co-star Robert Easton). His later film credits include the acclaimed 2006 period thriller The Prestige (which also featured Daniel Davis) and the 2007 blockbuster Transformers (written by Alex Kurtzman and Roberto Orci). In the latter film, Sheppard portrayed Captain Archibald Witwicky, the explorer who stumbled upon Megatron and grandfather of the film's central character, Sam Witwicky working with franchise leads Robert Foxworth, Glenn Morshower, and Frank Welker as well as Andy Milder, Michael Shamus Wiles, and Jamison Yang.
In addition to his Star Trek appearances, Sheppard portrayed two roles on the sci-fi series Babylon 5 and was a runner-up for the role of Ambassador G'Kar on the show, though the role eventually went to Andreas Katsulas. In addition, he had a recurring role as the holographic AI program known as "The Professor" on the series seaQuest DSV, alongside Richard Herd. Additionally, Sheppard was one of several Star Trek actors who voiced characters on the animated series Gargoyles. He voiced several characters on this show, including the father of Jonathan Frakes' character, David Xanatos.
Sheppard also guest-starred on such popular TV shows as MacGyver, Murder, She Wrote, and Frasier (starring Kelsey Grammer). He also appeared in the final episode of Quantum Leap, the hit science fiction series which starred Scott Bakula and Dean Stockwell. This episode featured Bruce McGill, Richard Herd, Stephen McHattie, Susan Diol, and Dan Butler, as well.
Later TV credits have included guest spots on Charmed (with Richard Lynch), Gilmore Girls (with Gregg Henry), and Criminal Minds (with Jennifer Hetrick). In addition, he appeared in an episode of Alias, the popular spy series created by J.J. Abrams, the director and producer of 2009's Star Trek. In 2009, Sheppard played war criminal Marcin Jerek, also known as Mr. Pain, on NCIS in "Broken Bird". Jerek was seen as a rival of Dr. Donald "Ducky" Mallard. In scenes depicting Jerek's past, Sheppard's son Mark was hired to play his father's character as a younger man.
Sheppard also had a supporting role as Bishop Francois Malveaux in the 1996 computer game Zork Nemesis along with Deep Space Nine guest star Stephen Macht.
In 2011, Sheppard appeared in Doctor Who, alongside his son who played a younger version of the same character. This places W. Morgan Sheppard and Mark Sheppard among the small number of actors who have appeared in both the Star Trek and Doctor Who franchises.