Before her career as a novelist, Kennelly wrote stories for The Manuscript while she attended Oregon State College, the Improvement Era, and pulp magazines.

Kennelly wrote five novels that were published during her lifetime: The Peaceable Kingdom; The Spur; Good Morning, Young Lady; Up Home; and Marry Me, Carry Me.

James was killed in an accident on the job in April 1921; Lula and her daughters then moved into Salt Lake City's Constitution Building, where her mother, Anna Matilda Johnson Olsen, lived and had her chiropractic office.

[1] Because of the war, Kennelly moved to Salt Lake City and various East Coast postings with Ullman, who had enlisted as a medical officer in the U.S. Air Force.

"[6] Another Kennelly story, That Day Was Grand, 1935, is told from the point of view of a young schoolgirl who idolizes a woman whom she considers the epitome of female beauty and perfection, possessing that ineffable quality of "cool".

In the story, Kennelly reveals the character Rose's egotism, unattractive lifestyle and taste, slovenliness, shallow values and poor judgment, and her likely fate should she continue to walk the path she has chosen.

Kennelly's first novel, The Peaceable Kingdom, was based on stories from the life of her maternal grandmother; it was published in 1949 and was a Literary Guild selection for December of that year.

[11] Good Morning, Young Lady (also a Literary Guild selection, in 1953) is a fictional coming of age novel but includes anecdotes based on the life of Butch Cassidy.

Like The Peaceable Kingdom and Up Home, it begins with stories of domestic life under polygamy in nineteenth-century Salt Lake City, but this novel follows its main characters and their descendants into the 1960s.

[14][15] At her death in 2005, Kennelly left other unpublished works, including a novel set in a millionaire's household in early-twentieth-century New York City; two late-life memoirs; some poetry; and a few stories and other shorter writings.