(written from a Production point of view)
Oliver McGowan (22 August 1907 – 23 August 1971; age 64) was a character actor famous for his many television guest appearances. In 1966 he played the Caretaker in the Star Trek: The Original Series first season episode "Shore Leave". He filmed his scene on Friday, 21 October 1966 at Africa, USA. 
He had a short motion picture career lasting ten years from 1957 to 1967, only appearing in five movies. His first motion picture was an uncredited role as a judge in the 1957 film The Joker is Wild (with Frank Sinatra). In his third movie, Palm Springs Weekend, he performed opposite the young Bill Mumy. He was uncredited for this role as well. He appeared in the 1966 film Stagecoach opposite Hal Lynch. His last film was Banning in 1967.
McGowan was mostly known for his 75 guest appearances. One of his earliest appearances, at the age of 49, was in an episode of Maverick alongside Arthur Batanides. He appeared in multiple episodes of Sugarfoot (1958; with William Schallert and Jon Lormer), Playhouse 90 (1959; with Celia Lovsky and Hal Needham), Route 66 (1961-1962; with Glenn Corbett and DeForest Kelley), Empire (1962-1963; with James Doohan, Bill Mumy, Bill Quinn, and Vic Perrin), Perry Mason (1964-1966; with Keith Andes, Anthony Jochim, and Arlene Martel), and Family Affair (1967-1969; with Brian Keith). Among the other shows he has appeared in is Father Knows Best (1959; with Jane Wyatt), The Man from Blackhawk (1960; with John Anderson), Sam Benedict (1963; with Brock Peters and Phillip Pine), Grindl (1963; with Felix Silla), The Farmer's Daughter (1964; with Barry Atwater and William Windom), Bewitched (1965; with Bill Mumy), My Three Sons (1966; with Susan Oliver), The Wild Wild West (1967; with George Murdock), Insight (1967; with Ted Cassidy), Mannix (1970; with Arlene Martel), and his last role in the Bracken's World episode "Diffusion" (1970; with Madlyn Rhue). McGowan was a regular on at least three television theater shows, including his first role in Letters to Loretta (1957-1958), Kraft Suspense Theatre (1964; with Brian Keith), and Bob Hope Presents the Chrysler Theatre (1965; with Michael Pataki).
He died only a day after his 64th birthday on the 23rd of August, 1971.