Maverick

Western movies were a big thing in the US during the time when a day or night at the theater meant a big feature film, a couple of b-movies, a serial, some cartoons and newsreels. When television started making an impact on the entertainment business a number of film and serial characters were developed into TV shows. The Lone Ranger, Rin Tin Tin, Hopalong Cassidy, for example. Most of these shows were more popular with the younger crowd, but they weren't necessarily produced with that intent.

On Tuesday night, Sept. 6, 1955, at 8:30 on ABC, the first episode of The Life and Legend of Wyatt Earp was aired and 4 nights later, at 10pm on CBS, Gunsmoke was launched. This kicked off the era of evening adult western dramas and very rapidly they accounted for a healthy percentage of the prime time programming.

Maverick hit the little screen in September 1957. Originally starring James Garner as Brett Maverick, the production team found that it sometimes took longer than a week to produce one episode so they added Jack Kelly as brother Bart Maverick, split the production team and began rotating "Brett" and "Bart" as leads. In 1960 Garner left the show so they added cousin Beau Maverick played by Roger Moore. The ratings began to slide so they added another Maverick, this time brother Brent played by Robert Colbert.

http://en.wikipedia.org/wiki/Maverick_%28TV_series%29