Prolific American supporting actor, a reliable presence in numerous classic prime-time TV shows for over half a century. One of three siblings, Hogan served in the U.S. Army during the Korean War. Upon his demobilisation he studied engineering at New York University, but an aptitude test suggested a more humanistic career path which prompted his enrolment at the American Academy of Dramatic Arts. Hogan made his theatrical debut off-Broadway in 1961 and moved to Los Angeles that same year to forge a solid career in episodic television, most frequently cast as no-nonsense authority figures, military middle-echelon or police officers. His first notable recurring role was as Reverend Tom Winter in the popular soap opera Peyton Place (1964). Hogan's sceptical Police Sergeant Ted Coppersmith in The Rockford Files (1974) led to several follow-up appearances in the short-lived spin-off series Richie Brockelman, Private Eye (1978). Hogan also played diverse characters in The F.B.I. (1965), Barnaby Jones (1973), Murder, She Wrote (1984) and Law & Order (1990). For his performance as the shrewd defense attorney Clarence Darrow in the off-Broadway play Never the Sinner (based on the Leopold & Loeb murder trial of 1924) Hogan was awarded the Outer Critics Circle Award.

Robert Hogan was diagnosed with vascular Alzheimer's disease in 2013, but was able to make sporadic TV appearances for another five years. He was married to the author Mary Barbera-Hogan.