Marshall Ambrose Neilan (April 11, 1891 - October 27, 1958) was an important pioneer motion picture actor, screenwriter, film director, and producer.

Born in San Bernardino, California, he was known by most as "Mickey." Following the death of his father, the eleven-year-old Mickey Neilan had to give up on schooling to work at whatever work he could find in order to help support his mother. As a teenager, he began acting in bit parts in live theatre, and in 1910 he got a job driving Biograph Studios executives around Los Angeles there to determine the suitability of the West Coast as a place for a permanent studio. Neilan is recorded as making his film debut as part of the acting cast on the American Film Manufacturing Company, Inc. western film production of "The Stranger at Coyote" released in 1912. Hired by Kalem Studios for their Western film production facility in Santa Monica, Neilan was first cast opposite Ruth Roland. Described as confident, but egotistical at times, Neilan's talent saw him directing films within a year of joining Kalem. After acting in more than seventy silent film shorts for Kalem and directing more than thirty others, Neilan was hired by the Selig Polyscope Company then Bison Motion Pictures and Famous Players-Lasky Corporation.

At the end of 1916, Marshall Neilan was hired by Mary Pickford Films where he directed Ms. Pickford in several important productions including Rebecca of Sunnybrook Farm and The Little Princess in 1917, plus Stella Maris, Amarilly of Clothes-Line Alley, M'Liss in 1918, and Daddy-Long-Legs in 1919.

Having all but given up acting, Neilan's directing successes led to him creating his own production company and between 1920 and 1926, Marshall Neilan Productions made eleven feature-length films almost all of which were distributed through First National Pictures. He received critical acclaim for directing and producing such films as Bits of Life and The Lotus Eater In 1929, he was hired by RKO Radio Pictures but had difficulty adapting to directing the new talkies. That year he directed Rudy Vallee and Marie Dressler in the talking film, The Vagabond Lover and although Dressler received high praise for her acting, the film was a commercial and critical failure.

Marshall Neilan had married actress Gertrude Bambrick in 1913 with whom he would have a son, Marshall Neilan, Jr. who worked in the film industry including as a successful film editor. The marriage ended in 1921 and a year later he married actress Blanche Sweet whom he directed on several occasions. They divorced in 1929.

Early in his career Neilan had done as most others in the pioneering days of film and helped out in many areas of filmmaking through performing, directing, and writing. A talented screenwriter, in 1930 he wrote the story for the Howard Hughes film, Hell's Angels. He was hired by Hal Roach Studios for whom he directed a few films in 1930 and made his final directorial effort in 1937. Having battled alcoholism for a large part of his adult life, twenty years after he made his last film, Neilan returned to acting on the screen in a small role portraying an aging and less than enlightened United States Senator in the Elia Kazan film, A Face In The Crowd.

In recognition of his contribution to the motion picture industry, in 1940 the Directors Guild of America conferred on him an "Honorary Life Member Award." He later received a star on the Hollywood Walk of Fame at 6233 Hollywood Blvd.

Marshall Neilan died in Los Angeles in 1958 of throat cancer and was interred there in the Angelus Rosedale Cemetery.

In the early days of silent pictures, Marshall Neilan was a top director for Goldwyn Pictures. He had also directed a small number of Louis B. Mayer's independently produced melodramas, but there was a mutual dislike between the two men. During the festivities inaugurating the merger of Metro and Goldwyn Pictures on April 26, 1924, Neilan grew disgusted at the prospect of listening to Mayer's speech and interrupted everything by ordering his cast and crew back to the set of Tess of the D'Urbervilles (1924). Mayer later viewed the picture and ordered the downbeat ending re-shot over Neilan's loud protests. Mayer, wanting to instill his absolute authority over all production matters, held firm. The prospect of working for Mayer in the new Metro-Goldwyn super-studio was unbearable and Neilan quit. His was the first outright desertion from the studio that others over the next three decades would aspire to be a part of.