In March 1841, Dorothea Dix's life changed forever when she went to a Massachusetts jail to teach a Sunday-school class. There she bore witness to the standard American practice of caging the mentally ill in prisons and poorhouses in unsanitary and unheated rooms. At that moment, Dix found her cause. Before long, she dedicated herself to exposing the inhumane ways in which the country generally treated its mentally ill and lobbying for the establishment of hospitals to treat and care for them. Although plagued with personal illness, she remained intrepid, and in one seven-year period she succeeded in convincing twelve state legislatures to fund asylums. With the outbreak of the Civil War, Dix directed her unrelenting zeal for doing good toward the medical needs of the Union armies. In June 1861 she became superintendent of women nurses for military hospitals, a post she held until the war's end in 1865.

One of the mental hospitals that Dix founded was St. Elizabeth's in Washington, D.C. Like so many of the institutions that owed their existence to Dix, St. Elizabeth's commissioned a portrait of her, and this painting hung for many years on its walls.