Billingsley's guest spots on TV included Naked City, Gunsmoke, Route 66, Dr. Kildare, Wagon Train, The Man from U.N.C.L.E., Mannix, Hawaii Five-O, Police Story, Alice, Baretta, and The Amazing Spider-Man.
Naked City (1963 episode "Walking On Hot Coals") (Clara Espuella)
New York City | Mexico City | Kansas City, Missouri | Kansas City | Salt Lake City | Quebec City | Oklahoma City | City of London | city | Vatican City | New York City Subway | Panama City | Kansas City Chiefs | Kansas City Royals | Sex and the City | Mayor of New York City | Atlantic City, New Jersey | Utrecht (city) | Cork (city) | New York City Ballet | Manchester City F.C. | Jersey City, New Jersey | New York City Opera | Guatemala City | Atlantic City | Quezon City | City College of New York | Ho Chi Minh City | Groningen (city) | Birmingham City F.C. |
Among the television series in which he appeared are Barney Miller, Rothman, The Incredible Hulk, All in the Family, Barnaby Jones, The Jeffersons, Maude, Kojak, The Untouchables, Have Gun, Will Travel, Naked City, T Men in Action, and The Big Story.
He made numerous appearances in such programs as Studio One, Kraft Television Theatre, Armstrong Circle Theatre, Naked City, The Defenders, Dr. Kildare, and Gunsmoke, among many others.
Born in Kiel, Germany, he wrote for many 1960s and 1970s television shows including Naked City, Mannix, The Time Tunnel, Police Woman, Star Trek ("The Galileo Seven" and "Dagger of the Mind"), Gunsmoke, Have Gun — Will Travel, The Paper Chase and Lost in Space.
Other performances include a minor role in the film Five Miles to Midnight (1962), as well as roles on the TV series Naked City (1961), Search for Tomorrow (1971–1973), where he played Dr. Gary Walton and The Secrets of Isis.
He hosted The Naked City (a radio show on FBi Radio in Sydney) along with his wife Miss Death and Coffin Ed until 2010.
Upon his return to Great Britain, he joined Radio Caroline South (where he used Jack Costanzo's version of the "Naked City Theme" as his signature tune, subsequently working for Radio Luxembourg and Radio London.