In New York City, she founded the "Musical Aid Guild" for poor students of ability, which was afterwards absorbed by the Metropolitan Conservatory of Music. During this period, she also appeared upon the public lecture platform in advocacy of
woman suffrage. and William Warner Jr. (d. 1900). Following the death of her children, Penfield took up the study of law at
Brooklyn Law School (LL.B., 1916), Penfield was admitted to practice law in 1916. She thus became one of the most conspicuous figures in suffrage work. Penfield also served as chair of the national committee to establish the representative district form of organization for suffrage work throughout the country. She resumed her work in New York City, and became actively engaged in many sociological movements as well as church and club work. She worked as a lecturer and college examiner of manuscripts, as well as a teacher of parliamentary law, and also a singer. During
World War I, Penfield was in charge of the department of practical law for women at Brooklyn Law School of
St. Lawrence University. She was the Honorary President of the Woman's Practical Law Association; honorary national vice-president of
Phi Delta Delta; and a member of the Board of Directors of the International Marriage and Divorce Committee. Penfield was a prominent member of many women's organizations, including the
Sorosis,
College Equal Suffrage League,
Daughters of the American Revolution,
Daughters of 1812, Westchester Woman's Club, National Woman Lawyers Association (counsel for State of New York), American Bar Association, New York County Lawyers' Association, Bronx Woman's Club, Kappa Kappa Gamma Sorority, Daughters of Indiana in New York,
United Daughters of the Confederacy, and
National League of American Pen Women. ==Personal life==