Florence Allen participating in a march for women’s right to vote.

Florence was heavily involved in the women's suffrage movement after she received her undergraduate degree from Western Reserve University. She participated in both the Ohio and New York women’s suffrage groups and attended many of their meetings and rallies.

In 1913, Florence and her law school friend, Bertha "Bert" Miller, took part in the "Votes for Women" pilgrimage. Demonstrators, led by Rosalie Jones marched from New York City to Washington D.C..