This is indeed a true Los Angeles style, devised in the early 1930s, and flourishing and evolving through the 1960s. As an architectural style (as opposed to interior design), it is a “modernized” neo-Georgian/Colonial style. There can be French and more modern influences as well. The world of the 1920s came to an abrupt end in 1929. Soon Europe was in turmoil with the rise of Fascism and threats of another great global war. At the same time, John D. Rockefeller, Jr. was rebuilding colonial Williamsburg. All these factors led to a “craze” for anything more authentically American. On the West Coast, there was a shift away from the European influences that dominated architecture up to that point. Furthermore, back on the East Coast the Art Deco style was turning heads.
Hollywood Regency infuses the Georgian/Colonial with more organic and streamlined details, characteristic of the Art Deco and modernist movements. The simplicity of the style, focused on flat wall surfaces, with carefully chosen details, does owe something to the adobe and stucco architecture of California. The most famous Los Angeles architects working in the style were John Elgin Woolf (who actually is the least famous but most prolific), Paul Revere Williams, and Wallace Neff.