Working steadily in radio since the 1940s, often uncredited, Burr was a leading player on the West Coast. He had a regular role in Jack Webb's first radio show, "Pat Novak for Hire" (1949), and in "Dragnet" (1949–50) he played Joe Friday's boss, Ed Backstrand, chief of detectives. Burr worked on other Los Angeles-based series including "Suspense", "Screen Directors Playhouse", "Yours Truly, Johnny Dollar", "Family Theater", "Hallmark Playhouse" and "Hallmark Hall of Fame". He performed in five episodes of the experimental dramatic radio anthology series "CBS Radio Workshop", and had what is arguably his best radio role in "The Silent Witness" (1957), in which his is the only voice.