(written from a Production point of view)
O'Loughlin began his career at Warner Bros. in the 1950s where he created the backgrounds for many Looney Tunes and Merrie Melodies shorts, including the Academy Award-winning Knighty Knight Bugs (1958). In the 1960s, he began working on Pink Panther cartoon shorts for DePatie-Freleng Enterprises, including their first effort, the Academy Award-winning The Pink Phink (1964). He also did background work for Hanna-Barbera cartoons such as Jonny Quest.
In addition to Star Trek, other Filmation series on which O'Loughlin worked include Fat Albert and the Cosby Kids, The New Adventures of Mighty Mouse and Heckle and Jeckle, He-Man and the Masters of the Universe, and BraveStarr. He also worked on Filmation's animated movies Flash Gordon: The Greatest Adventure of All (featuring the voices of Ted Cassidy, David Opatoshu, and Vic Perrin and written by Samuel A. Peeples), Mighty Mouse in the Great Space Chase and The Secret of the Sword (both featuring the voice of Alan Oppenheimer), and Pinocchio and the Emperor of the Night (directed by Hal Sutherland and featuring the voices of Scott Grimes, Frank Welker and William Windom). He also continued working for Warner Bros. on their compilation films The Looney, Looney, Looney Bugs Bunny Movie, Bugs Bunny's 3rd Movie: 1001 Rabbit Tales, and Daffy Duck's Quackbusters.