She was based at the women-only Wellesley College, Massachusetts, where she created new courses in political economy, in line with her personal belief in social change.

Among other admired works, Coman wrote The Industrial History of the United States and Economic Beginnings of the Far West: How We Won the Land Beyond the Mississippi.

A believer in trades unionism, social insurance and the settlement movement, Coman travelled widely to conduct her research, and took her students on field trips to factories and tenements.

[1][4] Because Coman believed that economics could address social problems, she urged the Wellesley administration to offer courses on the subject, and in 1883, she taught the college's first political economy class.

[4] That same year, she turned down the offer of a position as dean of women at the University of Michigan, stating that she preferred to remain at Wellesley and continue teaching.

[4]: 36 Her 1912 work Economic Beginnings of the Far West: How We Won the Land Beyond the Mississippi was considered by contemporaneous scholars to be her magnum opus,[6]: xi [2]: 166 [a] and "one of the most important fruits of the Carnegie Foundation for the Advancement of Teaching.

[3] Coman studied social insurance in England, Spain, Denmark, and Sweden, but poor health prevented her from continuing her research.

[3][1] For 25 years, Coman lived in a "Boston marriage"[18]: 192  with Wellesley professor and poet Katharine Lee Bates,[19]: 190  the author of "America the Beautiful".

[5]: 176  Coman frequently traveled for her research on economic history; she visited Europe, the American West, Scandinavia, and Egypt.

At the time, medical doctors did not understand the nature of breast cancer, its causes or its treatments, so the prognosis for Coman was poor.

[21] According to cancer historian Ellen Leopold, in the days after Coman's death, Bates wrote a memorial to her that was designed to be circulated privately among the women's close friends and family.

[21]: 61 [23] Leopold believes that the book, For Katharine Coman's Family and Innermost Circle of Friends, is the first breast cancer narrative in American literature.

[20][e] The book's title emerged from the fact that the "two Katharines," as the women were known, would send each other sprigs of yellow clover as tokens of affection.

[24] A review of Coman's book Economic Beginnings of the Far West: How We Won the Land Beyond the Mississippi (1912) in the San Francisco Chronicle stated that "the author is one of those new women who have shown what may be accomplished in the way of research by method and industry and a great deal of enthusiasm.

"[25] In a 1913 review of her book, economist Thomas Nixon Carver praised Coman's narrative style and lively prose.

[4] The University of Michigan "Naming Project" notes that she was one of the first historians to use local newspaper articles and government documents as primary sources in her teaching and writing.

[4] In 2011, The American Economic Review commemorated its first hundred years by publishing a list of the top twenty articles in the journal's history.

"[29]: 49 O ashes, memory of moral love, Sealed in your urn beneath the greensward, pure From evil, what am I to weep above Your beautiful and tranquil sepulture?