Gunsmoke is an American Western television series developed by Charles Marquis Warren and based on the radio program of the same name. The series ran for 20 seasons, making it the longest-running Western in television history. The first episode aired in the United States on September 10, 1955, and the final episode aired on March 31, 1975. All episodes were broadcast in the U.S. by CBS. In the United Kingdom, Gunsmoke was originally broadcast under the title Gun Law.
It was originally a half-hour program filmed in black-and-white, then expanded to an hour with season seven and began filming in color in season 12. During its run, 635 episodes were broadcast, of which 233 were 30 minutes and 402 were an hour. Of the latter, 176 were in black-and-white and 226 were in color. During season two, Gunsmoke became one of the 10 most popular American television programs and moved to number one in the third season. It remained so until 1961 and stayed in the top 20 until 1964. The series returned to prominence in 1967 following a shift in programming time from Saturday to Monday night. From there, Gunsmoke remained in the top 20 for the next seven years, dropping out only in its final season which ended March 1975; CBS canceled the series two months later, with then-vice president Alan Wagner saying, "It's better to get rid of a program one year too soon than one year too late." Between 1987 and 1994, five films based on the series were aired.
Gunsmoke is set in and around Dodge City, Kansas, in the post-Civil War era and centers on United States Marshal Matt Dillon (James Arness) as he enforces law and order in the city. In its original format, the series also focuses on Dillon's friendship with three other citizens of Dodge City: Doctor Galen "Doc" Adams (Milburn Stone), the town's physician; Kitty Russell (Amanda Blake), saloon girl and later owner of the Long Branch Saloon; and Chester Goode (Dennis Weaver), Dillon's assistant. In season eight (1962–63), a fifth regular character was added to the cast: blacksmith Quint Asper (Burt Reynolds), who remained until the end of season 10 (1964–65). Dennis Weaver left the series during season nine (1963–64) and was replaced by Ken Curtis as Festus Haggen, who became deputy to Marshal Dillon. In season 11 (1965–66), another deputy, Clayton Thaddeus Greenwood (Roger Ewing), was added to the cast. Ewing's character was replaced in season 13 (1967–68) by Newly O'Brien (Buck Taylor). Amanda Blake left the series at the end of season 19 (1973–74) and was replaced in the final season by a new character, Miss Hannah, portrayed by Fran Ryan.