[3] At the turn of the 20th century when the film industry was still in its infancy, Marion was employed at Biograph Studios in New York City as a sales manager as well as a screenwriter in collaboration with head writer Wallace McCutcheon.

Needing capital, they obtained financial backing from wealthy Chicago businessman and film distributor, George Kleine.

[5] Immediately successful, Marion proved to be an innovator and a businessman with a social conscience when he raised actor's wages to five dollars a day, thereby forcing the rest of the industry to follow suit.

The Kalem company achieved a first in the film industry when, upon the urging of Gene Gauntier, who had brought the company success with the Girl Spy serial films in which she had starred,[6] Marion sent Gauntier, director Sidney Olcott and a crew to Ireland in 1910 to make A Lad From Old Ireland, the first ever U.S. motion picture to be shot on location outside of the United States.

In November 1917, given his experience in the film industry, Marion was appointed to be the director of the offices the Committee on Public Information created in Spain and Italy.