"Gunsmoke" is the longest-running American prime-time drama TV series to date with 20 years and 633 episodes.
"Gunsmoke" was created by writer John Meston and producer Norman MacDonnell as a radio series that premiered on CBS in 1952. Many of the early television episodes are adaptations of Meston's radio scripts. The radio series ran for more than 400 episodes and lasted until 1961.
James Arness and Milburn Stone are the only two regulars to stay with the show for its entire 20-year, 633-episode duration on CBS. There was one brief exception, when Stone was replaced by another "doctor" while he was recovering from a heart attack.
Slated to be canceled in 1967 due to low ratings, but then-CBS president William Paley reversed the decision. He moved the show from Saturdays to Mondays (cancelling Gilligan's Island in the process), placing it back in the Nielsen's Top Ten (Paley and his wife were both big fans of the show).
Rumor has it that Rex Koury had so little time to pen the theme song that he hastily scribbled it while in the bathroom. It was originally written for "Gunsmoke" when it was a radio show and later adapted for TV.
The series was set in the 1870s. Kansas entered the Union in 1861. The Marshals Service provided local law enforcement in territories, not in states. The duties Matt Dillon performed would have been handled by a town Marshal or county sheriff (in this case, Ford County). Each state (or federal court district) had one US Marshal, who was in charge of all the Deputy US Marshals in that particular jurisdiction; Matt Dillon would have been a Deputy US Marshal.
The actress originally offered the part of Miss Kitty, Polly Bond (aka Polly Ellis), turned it down due to her recent (at the time) marriage to actor Tommy Bond in 1953.
This show, along with The Life and Legend of Wyatt Earp, helped launch the great era of the TV western. Westerns became so popular on TV that by the end of the 1950s there would be as many as 40 of them airing in prime time.
According to "The Complete Directory to Prime Time Network and Cable TV Shows" (8th Edition, pg. 495), John Wayne was the first choice to play Marshal Matt Dillon, but he declined because he did not want to commit to a weekly TV series. He did, however, recommend his friend James Arness for the role, and gave the on-camera introduction in the pilot.
Gary Busey's character Harve Daley was the last man killed on the show.
The gunfight between Matt Dillon and an unknown gunman that opened every episode was shot on the same main street as that used in High Noon.
Dennis Weaver felt his first audition for Chester did not go well, so he begged them to let him do it again, but this time with his famous country accent. He got the part.
Denver Pyle and Raymond Burr were both considered for the role of Matt Dillon.
After sixteen seasons, the producers decided to let Milburn Stone choose Doc's first name. Stone chose Galen, which was the surname of an ancient Greek physician and medical researcher.
No one told the cast about the series being canceled. Many of them read about it in the trade publications.
In Spanish-speaking countries, the series is known as La ley del revólver ("The Law of the Gun").
Three of the children from "The Brady Bunch" appeared in episodes: Christopher Knight (Peter); "The Miracle Man", Eve Plumb (Jan); "Gold Town", and Susan Olsen (Cindy); "Abelia" and "A Man Called Smith".
All four senior officers of the original "Star Trek" appeared in separate episodes: William Shatner (Captain Kirk); "Quaker Girl", Leonard Nimoy (Mr. Spock); "Treasure of John Walking Fox", "Call Him Wonder", "The Search", "A Man a Day", DeForest Kelley (Dr. McCoy); "Indian Scout", and James Doohan (Scotty), "Quint Asper Comes Home".