[1] In 1870, she graduated from Lake Erie College and taught for the following ten years in the Pennsylvania public school system.

[1] After graduating from Howard, Gillett formed a law partnership with a man named Watson J. Newton, after being his associate for eighteen years.

[6] As Gillett became more involved in legal matters, her colleague and friend, Ellen Spencer Mussey, sought her assistance in the education of women in the field of law.

[2] Within a few years, the program had expanded, and several prominent Washington, D.C., attorneys were brought in to assist Although Mussey and Gillett had not intended to establish an independent law school, when Columbian College (now George Washington University) rejected their request to take on the women they had educated for their final year of education—on grounds that "women did not have the mentality for law".

[9] The purpose of this club was to advocate for women's standing in society and support them through their educational and working careers.

At the time of her death was Dean Emeritus of the Washington College of Law and Chairman of the Legal Branch of the National Woman's Party.

Gillett died on January 23, 1927,[5] after contracting pneumonia while confined to her bed after breaking her hip the previous October.