She was often cast in comedies and Westerns, most notably being identified in 1915 as a "leading lady" in a series of shorts starring Tom Mix, who during the silent and early sound eras was promoted as the "Cowboy King of Hollywood".

[6] The federal census of 1910 shows that in Los Angeles Sue earned income for her family by renting rooms in their house to several boarders, and that Louella—just shy of 19 years old at the time—was employed as a bookkeeper in a nearby grocery store.

[5] Within a few years, however, young "Lula" found work in Hollywood's rapidly growing film industry, initially performing in serials and in stand-alone shorts as an extra and in other small uncredited parts.

[3][b] In one of those Westerns, A Child of the Prairie, Maxam's own three-and-a-half-year-old daughter Norma is featured and identified in 1915 trade publications as a "Los Angeles product" and "the youngest member of the Selig Polyscope Company of players".

[7][8][c] In its April 23 issue that year, The Photoplayers' Weekly describes "Baby Norma Maxam" on the set:She is at the studio on every possible occasion and is beloved and petted by all the cowboys, whom she loves in return...she is too fearless around horses and all animals.

Photoplayers' Weekly once again highlights Maxam in its July 8, 1915 issue, featuring a portrait of the actress on its front cover, an image that carries the tagline "Star of Western Dramas and Comedies".

Yet, despite her screen success with Mix, she declined the offer in the summer of 1915 to relocate from California to work at a new studio in Las Vegas, New Mexico, one being constructed specifically for the production of the cowboy star's lucrative films.

[10] "Miss Louella Maxam", Photoplayers' Weekly reported, "one of the best known leading women in screen dramas of western life, refuses to sacrifice her home in Glendale, which is the reason she did not accompany Thomas Mix."

[10] Later in 1915, after declining the move to New Mexico and leaving Selig, Maxam began working for Universal, performing there in Her Prey, Manna, The Phantom Fortune, The Measure of Leon Du Bray, and The Fair God of Sun Island, which was filmed on location in Laguna Beach.

[11] In late November, Louella spent two weeks on location again with other "Universalites" in the snowy "Bear Lake regions" of Southern California, filming and co-starring with Sydney Ayres in John o' the Mountains, a three-reel "Canadian Northwest" drama written by F. McGrew Willis.

In early November 1916, shortly after Motion Picture News published the noted directory, Motography announced she had left Keystone "to join her husband [Brunton], who is one of the Signal players.

Peter Milne, film critic for Motion Picture News, gives a rather vague assessment of the actors' performances in his September 22, 1917, review: "The principal roles are handled by Jack Livingston, Louella Maxam and George Ches[e]bro, a trio who distinguish themselves averagely.

"[25][26] For the American Film Company, Maxam performed with J. Gordon Russell in portraying a poor starving couple in The Mantle of Charity, a five-reeler initially released for preview in September 1918.

[33] One 2019 online reference includes Maxam, without a cited source, as a cast member in the May 1921 Canyon release The Raiders, a lost film that starred Farnum and Claire Windsor.

[42] California death records document that Merna Marguerite [Modie] Levack was born April 23, 1911, in Los Angeles—the same day, year, location, and of the same parents as cited on the birth certificate of Norma Maguerite Keller.