Photographer and designer William Mortensen was born on January 27, 1897 in Park City, Utah, to Danish immigrants. Following his graduation from high school, Mortensen served as Private in 13th regiment of the U.S. infantry during World War I, operating as a painter who recorded the events he witnessed. Following his discharge he briefly studied at the Art Students League in New York before traveling throughout Greece in 1920. On his return to Salt Lake City he taught art at East Side High School for a year before taking a job chaperoning his friend's sister, then-aspiring actress Fay Wray, on her move to Hollywood. He found employment as a set painter, prop builder, and designer through the directors Cecil B. DeMille and King Vidor. At this time, he also took up photography.

With the popularity of silent films in the 1920s, he found his niche, photographing actors and film stills in a pictorial manner, styling the compositions himself while on set. He was particularly drawn to theatrical imagery and focused on horror, fantasy, and hisorical films and actors. He employed drawing and painting techniques and tools to manipulate the photos for a variety of effects, furthering the wild, sometimes grotesque, dreamscape nature of his imagery. His work was compared with Goya and Bosch not only in its style but its subject matter. Debates between himself and other photographers of the modern realist movement were spurred in the 1930s, with a particularly volatile written debate between himself and Ansel Adams in the pages of Camera Craft magazine (Adams would later call him the "antichrist"). Despite criticism, Mortensen stuck to his belief that his work was as much an art form as any kind of photograhy. His work was published in the Los Angeles Times, Vanity Fair, and the American Annual of Photography, among other publications.

Mortensen relocated to Laguna Beach in 1931 and opened his studio, the William Mortensen School of Photography. He taught classical portraiture and other basic elements of composition as well as his own manipulation techniques. He found his greatest financial success in portraiture and became known for his images of popular actors and other notable figures in Los Angeles, among them Rudolph Valentino, Fay Wray, Jean Harlow, Peter Lorre, and more. He was honored with the Hood medal from Royal Photographic Society in 1949, and a biopic on his theatrical photography - particularly in horror - was produced by Richard Soltys in 1963, titled Madonnas and Monsters: the World of William Mortensen, narrated by Vincent Price. Mortensen died in 1965 in Laguna Beach. 

With the advent of World War II and the emergence of photojournalism, Mortensen's work was largely forgotten by the late 1960s. However, recent interest in his techniques were revived in the early 2000s. In 2014 the Stephen Romano Gallery hosted an exhibition and published a book of his work, both titled "William Mortensen: American Grotesque," and several more books have been published since.