Alice Merrill was born in Fillmore, Utah, on 2 January 1868 and was the fourth of fourteen children born to Clarence and Bathsheba Smith Merrill. She began schooling at the old rock schoolhouse in Fillmore, but at the age of nine went to Salt Lake City to live with her recently widowed grandmother, Bathsheba Bigler (Mrs. George A.) Smith. After completing grade school, she attended the University of Deseret where she was graduated in 1887 with a degree in pedagogy. She was especially interested in art, art education, literature, and writing.

She married George H. Horne, a Salt Lake City banker, and subsequently bore six children: Mary, Lyman, Virginia, George H. Jr., who died in infancy, Zorah, and Albert. George Horne died in 1934.

She first taught school in Fillmore, and while George was on a mission for the LDS Church to the southern states, she was a teacher at Washington School in Salt Lake City, and she continued as an educator during the ensuing years.

Alice studied art at the University of Deseret, the Art Institute of Chicago, and privately under George M. Ottingher, J. T. Harwood, John Hafen, Herman Haag, Mary Teasdel, and Henry Taggart. She became closely associated with almost all the prominent Intermountain artists. Lee Greene Richards dedicated a portrait of Bathsheba Smith to "Mother Horne," the name by which Alice was fondly referred to by the artists.

In 1891, only twenty-three years old, Alice was appointed chairman of the Utah Liberal Arts Committee for 1893 Columbian Exposition in Chicago, for which she published a book of poems written by women poets of Utah. She also supervised the preparation of various creations of Utah women that were exhibited in the Woman's Building in Chicago.

In 1898 Alice was elected a member of the Utah House of Representatives, the second woman to serve in that body. She introduced and shepherded through a bill for the state to create an art institute--a landmark bill, as it inaugurated the first art institute in the United States--to encourage the fine arts (art, music, literature, and dance) in Utah; to hold an annual art exhibition, and to initiate a state-owned art collection. In her honor the state collection is called the Alice Art Collection. Mrs. Horne also sponsored a law that provided four-year, tuition-paid teaching scholarships to students at the University of Utah; and she served as chair of the University Land Site committee that chose the present location of the University of Utah.

In 1901 Mrs. Horne was made a member of the General Board of National Women's Relief Society of the LDS Church, and served on the board for fourteen years. As chair of the Relief Society's art committee, she prepared lessons on art appreciation, landscape study, and architecture that were published for use in their classes. She also contributed many articles for the Improvement Era, Juvenile Instructor, Relief Society Magazine, and Woman's Exponent. As chair of the infant care committee for the society she also sponsored a "Clean Milk for Utah" campaign that resulted in more rigid inspections standards for milk sold in the state. As a part of this effort, she established four free milk stations in different parts of Salt Lake City for the benefit of undernourished and underprivileged babies.

In 1904 Mrs. Horne represented the National Women's Relief Society and the United States at the International Congress of Women in Berlin, Germany, and gave two addresses to the Congress, one on the Utah art movement and one on women in politics, recounting her experiences as a legislator. She served for several years as Utah chair of the International Peace Committee. She served as secretary, historian, and second president of the Daughters of the Utah Pioneers, and participated in the organization of the Daughters of the Revolution in 1896. She later served as a state regent.

Mrs. Horne's most important contribution to Utah, however, was in art. In the 1920s, 1930s, and 1940s she promoted Intermountain artists by exhibiting and selling their paintings so they could earn a livelihood as artists. She advised art patrons, "In each home should hang a good picture, no matter how small." She held art exhibitions throughout the state, especially in prominent locations in Salt Lake City. "If you really want to learn what art is, live with it: make it a part of your home and of your experience," she advised. She determined that Utah children would have the advantage of original art around them by inspiring thirty-seven art collections in the state's schools, with scores of paintings by Utah artists. She also wrote and published Devotees and Their Shrines: A Handbook of Utah Art (1914), a child's play, Columbus Westward Ho! (1922), and a periodical, Art Stands, that carried news of art in Utah.

In the 1930s she organized the "Smokeless Fuel Federation" to eliminate the environmental hazard of coal as a home heating fuel. Horne Hall, one of the Heritage Halls constructed in 1956 by Brigham Young University, was named after Alice Merrill Horne.

Alice Merrill Horne died of a heart attack on 7 October 1948; she was eighty.