[4][5] After completing her undergraduate studies, Brandt started teaching history and classical languages in different colleges.
Her early work on social welfare attracted the attention of Edward T. Devine, who appointed her in 1902 as the secretary of the Charity Organization Society's Bureau of Labor Statistics.
Brandt served as a mentor to fellow social reformer Mary van Kleeck in New York City before World War I.
The Negroes of St. Louis: A Statistical Study is considered one of Brandt's notable works due to its groundbreaking conclusions.
One of her findings revealed that Black entrepreneurs had the tendency to draw in, close off, and target people of their own race.