Ward Bond didn’t really “leave” Wagon Train by choice — he died of a heart attack in November 1960 while the show was in production.

What was said

  • The on-show reason was not explained. Reports say Major Seth Adams simply disappeared from the series without a story explanation.
  • John McIntire was brought in to replace him as the new wagon master after Bond’s death.

In plain terms

The reason given in the real world was Bond’s sudden death, not a creative decision to write him out for another job or dispute.

Small detail

Some later discussion about the cast mentions tensions on set, but the core, documented reason for his departure was his fatal heart attack.

TL;DR: Ward Bond left Wagon Train because he died during production, and the show did not give an in-story explanation for his character’s exit.