Romanus was born in Barre, Vermont, the son of Eileen (née Maloof) and Dr. Raymond Romanos. He lived in West Hartford, Connecticut, and in 1964 graduated from Xavier University with a bachelor's in philosophy, before studying acting with Lee Strasberg at the Actors Studio in New York. His younger brother Robert is also an actor. They both appeared in some episodes of MacGyver in the 1980s. He is of Lebanese descent.
On May 20, 1967, he married Tina Bowman. They had a son named Robert before divorcing in 1980. Romanus has been married to Oscar-nominated costume designer Anthea Sylbert since August 11, 1985.
In 2004, Romanus and his wife moved to the Greek island of Skiathos and since then he has focused on writing. In 2011, he published his memoirs, Act III (Aiora Press, Athens, and Armida Publications, Nicosia), and first novel, Chrysalis (Armida Publications). In 2012, Act III was short-listed for the International Rubery Book Award.
