An active abolitionist, Howland taught at a school for young black girls in Washington D.C from 1857 to 1859. During the Civil War she worked in Arlington, Virginia teaching freed slaves to read and write as well as administering to the sick during a smallpox outbreak.
In 1882 she assumed control over the Sherwood Select school as owner and consulting head, a position she held up to her one hundredth year in 1927, at which point it was renamed the Emily Howland high school by the New York State Board of Regents.
She became the first female director of a national bank in the United States, at the Aurora National Bank in New York in 1890, where she served up to her death.
Howland was also active in women's suffrage and peace. Also active in temperance, she was a member of the Women's Christian Temperance Union.
In 1926 she received the Litt.D degree from the University of the State of New York. She was the first woman to have this honor conferred upon her from this institution.
She was also the author of the book Historical Sketch of Friends in Cayuga County.