The show was slated to be cancelled in 1967 due to low ratings, but CBS President William Paley, who was a big fan, reversed the decision. He moved the show from Saturdays to Mondays (cancelling Gilligan's Island (1964) in the process), placing it back in the Nielsen's Top Ten.
James Arness received his draft notice in 1943, and trained at Camp Wheeler, Georgia, before shipping out for North Africa. He was assigned to the 3rd Infantry Division in time for the invasion of Anzio. Ten days after the invasion, he was severely wounded in the leg and foot by machine gun fire. He lost part of his foot, and received a medical discharge from the Army. When shooting movies or television shows, any scenes that required extensive walking would be shot early in the morning, before his feet and knees started giving out. For his service, he received: a Bronze Star, Purple Heart, European-African-Middle Eastern Campaign Medal with three bronze campaign stars, the World War II Victory Medal, and the Combat Infantryman Badge.
Denver Pyle and Raymond Burr were considered for the role of Matt Dillon. Pyle would appear as different characters in 14 episodes from season 2 through season 18.
Buck Taylor (Newly) was also requested by Jack Lord for the role of Dan "Danno" Williams on Hawaii Five-O (1968) at the same time he was up for the role of Newly O'Brian.
Dennis Weaver stated on his commentary about his time on this show that he seriously regretted giving Chester his limp. He hadn't realized how much work it would become to maintain in everything Chester did.