Appears In: Gunsmoke (1955-1975)
Portrayed By: James Arness
In terms of sheer amount of gunslinging, Marshal Dillon from Gunsmoke has outslung any other character on this list. Gunsmoke ran for 635 episodes, spanning two decades. Marshal Dillon remains the iron man of television leading man to this day. Only Kelsey Grammar's Frasier Crane appeared in more television episodes, but that took him two shows, Frasier and Cheers.
This longevity allowed the character to grow as the series progressed; Dillon grew more hesitant on the quick-draw, tiring a bit of violence as time marched on. We doubt Raylan Givens, also a U.S. Marshal, will have any similar evolution, largely because it would be hard to imagine another live-action show lasting 20 years.