A film producer creates the conditions for making movies. The producer initiates, coordinates, supervises and controls matters such as fundraising, hiring key personnel, and arranging for distributors. The producer is involved throughout all phases of the filmmaking process from development to completion of a project.
In the early 20th century, the producer also tended to wield ultimate creative control on a film project. With the demise of Hollywood's studio system in the 1950s, creative control began to shift into the hands of the director.
Changes in movie distribution and marketing in the 1970s and '80s gave rise to the modern-day phenomenon of the Hollywood blockbuster, which tended to bring power back into the hands of the producer. While marketing and advertising for films accentuates the role of the director, apart from a few well-known film makers it is usually the producer who has the greatest degree of control in the American film industry.
Traditionally, the producer is considered the chief of staff while the director is in charge of the line. This "staff and line" organization mirrors that of most large corporations and the military. Under this arrangement, the producer has overall control of the project and can terminate the director, but the director actually makes the film. The "line producer" is thus a producer who assists with day-to-day financial and production concerns "on the line" as the film is being made.