You might say that The Virginian was the original Man With No Name, and he predated Clint Eastwood's spaghetti western anti-hero by several decades. Owen Wister's original story, which provided the basis for 2 films (1929 & 1946), and a half-hour pilot commissioned by Screen Gems for Decision in 1958, was loosely adapted by Revue/Universal for NBC, and was the first 90 minute Western. Stablemate Wagon Train, which moved to ABC to make room, expanded to 90 minutes in answer.
James Drury, who was first cast for the Decision episode in 1958, was brought back 4 years later and headed an ensemble cast that, other than Doug McClure, seemed to go through a revolving door every so often. The Virginian (real name unrevealed) was the foreman at Shiloh Ranch in Medicine Bow, Wyoming, which was originally owned by Judge Henry Garth (Lee J. Cobb), who sold the ranch halfway through the 4th season when he was elected governor of Wyoming. Cobb, you see, left to work on the Derek Flint spy spoofs with James Coburn for 20th Century Fox. Morgan Starr, played by radio veteran John Dehner, purchased the ranch. However, Starr proved to be unpopular with the audience, and so the ranch began changing hands again.
Charles Bickford took over as the ranch owner in season 5, and after his passing two months into the 6th season, John McIntire (ex-Wagon Train) was brought in, just as he had succeeded Ward Bond on Wagon Train upon Bond's passing a few years earlier. In 1970, the series was given a total makeover, rechristened The Men From Shiloh, and the open created a look similar to the spaghetti westerns which had become popular. Percy Faith's driving score was replaced with a new theme by Ennio Morricone. McIntire was gone, replaced by Stewart Granger. Lee Majors, a year removed from The Big Valley, joined the show, making his debut with Universal.
The supporting cast's revolving door also included Tim Matheson (ex-Jonny Quest), Clu Gulager (ex-The Tall Man), and, in season 7, David Hartman, who left not long after to work on another Universal project, The Bold Ones.
From that 7th season, here's "Crime Wave at Buffalo Springs", as seen on INSP.