As the 60s were ushered in the kind of solid B westerns that Audie Murphy made were getting fewer and fewer made for the big screen. I'm guessing that someone said a television series was steadier income. So Audie took a flier at the small screen.
If you get a long running series like Bonanza or Gunsmoke that can be a steady money maker for you. But many of the screen's biggest names didn't quite make it in their efforts for a weekly television series. Much bigger names than Murphy's.
Whispering Smith failed to find an audience and ended after a half season. The character has been the title character for a number of big screen films, most notably Alan Ladd in 1948. His Whispering Smith was a railroad detective and the character fitted Ladd's soft spoken but menacing personality perfectly. Audie's character was also quiet and deadly, but he was a detective in the rapidly growing city of Denver's municipal police.
The other two characters were Audie's sidekick pop singer Guy Mitchell and their boss Captain Sam Buffington. For reasons still unknown but speculated Buffington killed himself. That and bad ratings guaranteed the show's early cancellation.
Whispering Smith just never found an audience in 1961 where there were a glut of westerns on television back in that day. If it had maybe Murphy's career course might have been different.