Cleaves lectured and had clinical practice in London, Paris, Leipzig, Berlin and New York.
From 1873-6, Cleaves worked as an assistant physician at the State Hospital for the Insane, Mt.
Pleasant, Iowa.
Cleaves was the first woman physician to regularly treat mental illness at that institution, she subsequently served as a member of the board of trustees.
From 1880-3, Cleaves was physician-in-chief of the Women's Department, State Hospital for the Insane, Harrisburg, Pennsylvania.
In 1885, Cleaves was appointed to the University of Iowa Medical Department's examining committee, "perhaps the first woman to serve in that capacity in the United States." In 1895, Cleaves founded the New York Electro-Therapeutic Clinic, Laboratory and Dispensary in New York City.
Her work there included the treatment of a large number of cases of neurasthenia among both male and female patients.Cleaves was a prolific author on topics concerning the use of radiation and electricity to treat illnesses.
Cleaves also invented a variety of instruments for such treatments.
Having an interest in the welfare and advancement of women, She organized the Des Moines Woman's Club and served as its first president.