Richard Diamond premiered on radio in 1949 and ran for three seasons in that medium. The part of the hardboiled detective was a natural for Dick Powell who had made over his apple-cheeked crooner image from the Thirties to one of film-land's premier tough guys. On the radio show Powell was a former NYPD detective who also served in the OSS in World War II. He who essayed the part of Philip Marlowe so well in Murder My Sweet had no trouble in making Richard Diamond a hit on radio when that venue was losing audiences and sponsors to television.
In 1957 he was offered the part to do again on television. But Powell who was a practical businessman as well as talented actor felt at this point the role demanded a younger man. Like John Wayne who recommended James Arness for Gunsmoke, another radio series transitioning to television, Powell hired David Janssen, a young contract player with Universal for Diamond. I did say 'hire' because it was Powell's Four Star Production Company that produced the show for television.
Janssen was also an inspired choice. I don't recall if the OSS part of his background was kept for television as it was a younger Diamond Powell wanted, but what was added was the legs and hands of Mary Tyler Moore as Sam the message center operator. We never saw her face, we were saved that for The Dick Van Dyke Show, but her legs were a thing of beauty indeed. And that sultry voice, YOIKES.
Moore was the only other real regular on the series, Janssen played a lone hand. Richard Diamond was a throwback to the Raymond Chandler/ Dashiell Hammett school of fiction detectives. He was a tough guy with a biting wit and his adventures were accompanied by a nice Man With A Golden Arm type jazz score.
Richard Diamond ran for three seasons and Janssen went on to his biggest success in The Fugitive. Still there are some who consider Diamond his best television work and I'd love for TV Land channel to dig up those episodes so a new generation can find out.