His Hollywood career began in 1909 as a lab assistant with the Essanay Film Manufacturing Company in Chicago.

[2] Seitz got his first chance to establish himself as lead cameraman in 1916, and he achieved great success with the director Rex Ingram, most famously on the Rudolph Valentino film The Four Horsemen of the Apocalypse (1921).

Highly regarded by director Billy Wilder, Seitz worked with him on the films noir Double Indemnity (1944), The Lost Weekend (1945), and Sunset Boulevard (1950), receiving Academy Award nominations for each.

[2] An example of a Seitz invention is the matte shot: a large painting is photographed separately and later added to a scene to expand it, add effects, and/or create a sense of depth in backgrounds.

A widower, he married screenwriter Marie Boyle in 1934 who raised his daughter Margaret Alice Marhoefer and later gave birth to a son, John Lawrence Seitz.