She became identified with the white-ribbon movement in Kansas City, Missouri, giving up her position as principal of a school to enter the work of the Woman's Christian Temperance Union (WCTU).

Her mother was Olive Ruruham, daughter of Major Elisha Burnham, who served in the Revolutionary War.

[2] She was educated in the public schools of New York and at Gouverneur Wesleyan Seminary, later pursuing a course of study for two years in Springfield, Massachusetts.

In May of that year, the WCTU members living in the state, met at Hannibal, Missouri and formally organized.

Young boys and old men were frequently seen drunk on the public streets of Missouri's towns and cities.

Thousands of men spent their weekly wages for beer and whiskey and then went home to their wives and children without money to buy bread, meat and clothing.

She rallied the forces with the skill of a major-general, drilling them with the thoroughness that her long experience as a teacher had caused to become second nature, and inspiring them with zeal.

[3] Hoffman had the advantage and privilege of intimate friendship with Frances E. Willard, Lady Henry Somerset, Susan B. Anthony, Mary Torrans Lathrap, and others.

[7] At the World's Congress of Representative Women (1893) in Chicago, Hoffman delivered an address entitled, "A Bird's-Eye View of the National Woman's Christian Temperance Union".

[5][6] Hoffman wanted woman to read widely on public questions, to inform herself on what the government is doing as well as on the latest style in dresses.

[5] Her health failing, Hoffman suffered an attack of pneumonia in 1908, and after an illness of four weeks,[5] died on February 13, 1908, in Kansas City.

[9][6] A biography with several memorial tributes was compiled by Carrie Lee Carter-Stokes, under the title Clara C. Hoffman, Prophet and Pioneer (Kansas City, n.d.).

[3] Hoffman was the only woman included in Floyd Calvin Shoemaker's Missouri's Hall of Fame: Lives of Eminent Missourians (1923).

[5] In the reading room of The State Historical Society of Missouri, at Columbia, is a marble bust statue of Hoffman.