I wondered about that. Just yesterday.

A sad day. First Killebrew, not Arness. 

I remember my parents listening to Gunsmoke on the radio. Marshal Matt Dillon was played by William Conrad on the radio series.

The radio series aired from April 26, 1952 ("Billy the Kid," written by Walter Newman) until June 18, 1961 on CBS. It starred William Conrad as Marshal Matt Dillon; Howard McNear as Doc Charles Adams; Georgia Ellis as Kitty Russell; and Parley Baer as Dillon's assistant Chester Proudfoot.

Conrad was one of the last actors who auditioned for the role of Marshal Dillon. With a powerful, distinctive voice, Conrad was already one of radio's busiest actors. Though Meston championed him, MacDonnell thought Conrad might be overexposed. During his audition, however, Conrad won over MacDonnell after reading only a few lines. Dillon as portrayed by Conrad was a lonely, isolated man, toughened by a hard life. MacDonnell later claimed "Much of Matt Dillon's character grew out of Bill Conrad." ^[4]

Meston relished the upending of cherished Western fiction clichés and felt that few Westerns gave any inkling of how brutal the Old West was in reality. Dunning writes that Meston was especially disgusted by the archetypal Western hero and set out "to destroy [that type of] character he loathed." In Meston's view, "Dillon was almost as scarred as the homicidal psychopaths who drifted into Dodge from all directions."^[5]

Chester's character had no surname until Baer ad libbed "Proudfoot" during an early rehearsal. The amiable character was usually described as Dillon's "assistant," but the December 13, 1952 episode "Post Martin," Dillon described Chester as Dillon's deputy. The TV series changed Chester's last name to Goode.

Interesting to note, his brother Peter Graves [TV series - Mission Impossible] died in March 2010.