Conversation so far:
What was Harrison Ford's first career move?
In 1964, after a season of summer stock with the Belfry Players in Wisconsin, Harrison Ford traveled to Los Angeles to apply for a job in radio voice-overs.
What was Harrison Ford's first film?
Harrison Ford's first known role was an uncredited one as a bellhop in Dead Heat on a Merry-Go-Round.
Did Harrison Ford appear in Dead Heat on a Merry-Go-Round with anyone notable?
Dead Heat on a Merry-Go-Round is a 1966 crime film starring James Coburn, Camilla Sparv, Aldo Ray, Nina Wayne, Todd Armstrong, Robert Webber, and Rose Marie.

Question: What was Ford's most successful film?
Self-contained rewrite: What was Harrison Ford's most successful film?