Roy was born on April 6, 1938, in Chicago, Illinois. During his formative years, he had wanted to become a doctor or football player - or, if one wants to believe his early press releases, both. He started in show business at a radio station, where he did everything: engineering, DJ shows, news and dramatizations. That led to an interest in acting in general. After a hitch in the army, he went to New York and then to California, where he started working in episodes of TV shows. Having made his professional acting debut as a teen-aged firebug in a 1957 pilot for the never-sold TV series, "Chicago 212", Thinnes spent several lean years "between engagements", working as a hotel clerk, vitamin salesman and copy boy to Chicago columnist 'Irv Kupcinet' .
Was originally hired to play Arthur Adamson in Alfred Hitchcock s final film, Family Plot , but Hitchcock had always wanted William Devane for the part. Devane was originally unavailable, so Hitchcock began filming with Thinnes in the role. When Devane became suddenly available one month into filming, Hitchcock unceremoniously fired Thinnes without explanation and replaced him with Devane (Hitchcock later claimed he was dissatisfied with Thinnes performance). The way Hitchcock handled the firing led to a famously public confrontation between the two men in a crowded Chasens Restaurant. Thinnes can be seen in several publicity stills from the production, but no footage apparently exists.
Best known as architect David Vincent in the 1960s cult television series, "The Invaders" . He appeared in a mini-series remake of that series, "The Invaders" , also in the role of David Vincent.
Served a hitch in the US Army as a Military Policeman.
He made guest appearances on both of the longest running prime time dramas in US television history: "Gunsmoke" and "Law & Order" .
He was considered for the role of Tom Hagen in The Godfather before Robert Duvall was cast.
