For five years she gave speaking tours on Celtic mythology at American universities, and in 1931 she was involved in a publicized immigration controversy when she attempted to become a citizen.

At Berkeley she was known for her colorful and lively persona, giving lectures while wearing the purple robes of a Druid, expounding on legendary creatures such as fairies and elves, and praising the benefits of talking to trees.

Her encyclopedic knowledge and enthusiasm for the subject of Celtic mythology attracted and influenced many of her friends and won her a wide audience among writers and artists in California, including poets Robinson Jeffers and Elsa Gidlow, philosopher Alan Watts, photographer Ansel Adams, and composer Harry Partch, who set several of her poems to music.

[2] Later in life she served as the "godmother" and inspiration for the Dunites,[3] a group of artists living in the dunes of San Luis Obispo County.

Her close friend, Irish revolutionary and actor, Maud Gonne illustrated both Lugh and Young's first story collection, Celtic Wonder-Tales (1910).

[10] Celtic studies scholar William Whittingham Lyman Jr. left the University of California, Berkeley, in 1922 and Young was hired to fill the post in 1924.

[11] She immigrated to the United States in 1925; according to Kevin Starr[12] she "had been briefly detained at Ellis Island as a probable mental case when the authorities learned that she believed in the existence of fairies, elves, and pixies".

[18] As of 1931 she had not received legal immigration status; Charles Erskine Scott Wood advised her to go to Victoria, British Columbia, in order to restart the process toward American citizenship.

In 1934 Young penned an enigmatic review of O'Shea's exhibition of charcoals at San Francisco's prestigious Palace of the Legion of Honor.

While living in a cabin behind John Varian's house there, Young finished writing The Tangle-Coated Horse and Other Tales, a 1930 Newbery Honor Book.

[23] She traveled with Adams and his wife Virginia to Santa Fe, New Mexico, in 1929, spending time with friends, visiting artists at the Taos art colony, and staying with Mabel Dodge Luhan.

[30] An archive of her papers is currently held by the Charles E. Young Research Library Department of Special Collections at the University of California, Los Angeles.

[35] One library catalogue summary of the 1988 selection, perhaps by its publisher Floris Books, implies that "Young's classic re-telling of Celtic stories" comprises all four earlier collections.