Supporting roles were an essential element in the theater long before the movies were invented, and they served much the same function that they would come to serve in motion pictures. Supporting actors were unnecessary in the earliest movies: short documentaries, called actualités , featured images from real life and therefore did not use actors at all, and others were short, staged scenes that featured only a very small number of performers. By the early twentieth century, film narratives became more complex and started featuring a hierarchy of characters similar to what had previously existed in the theater, with some roles playing a more prominent part in the plot's development than others. As movies grew longer and their narratives more elaborate, supporting roles were needed to flesh out the stories. Once Hollywood's star system began to take shape around 1910, the use of supporting players became more pronounced, with one or two stars taking the major roles in each film and an array of character and supporting actors handling the remaining, smaller roles.
Although supporting actors had appeared in movies since very early on, the category of Supporting Actor was not officially recognized by the Academy of Motion Picture Arts and Sciences until 1937, eight years after the Academy began giving out their annual awards. The inclusion of supporting actors in the Academy Awards ® was initially a way for the Academy to appease the members of the actors' union, the Screen Actors Guild, formed in 1933 as a response to studio business practices that actors felt were unfair, including cuts to and limits on actors' and writers' salaries, and a tightening of studio control of actors under contract. When the Academy sided with the studios in this dispute, the Screen Actors Guild denounced the organization and required its members to resign from the Academy. In 1936 the Screen Actors Guild, along with the Writers Guild and the newly formed Directors Guild, sent telegrams to its members encouraging them to boycott that year's awards