I wondered whether he worked for a company that distributed films to cinemas etc on loan for a fee
how about Renter.
As in, the man who travelled around with the films for the picture theatres to rent
Following up on that I think the word might perhaps be 'renter
s' which would make him a Film renters traveller, i.e. someone who worked as a travelling agent for a film rental company?
The word isn't master or writer.