Cole was an American Presbyterian missionary educator who played an important role in developing women's education in Siam. She was born in Illinois on 1 January 1855 and graduated from Western Female Seminary in Oxford, Ohio, in 1878. She served principal of the Chiang Mai Girls' School in the Laos Mission's Chiang Mai Station from 1878 until 1883. Working initially with her close friend, Mary Margaretta Campbell, she developed this school from the small girl's literacy class started by Sophia McGilvary. It was the first permanent Western-style school in northern Siam.

In 1885, Cole became principal of the Bangkok Girls' School under the Presbyterian Siam Mission, and she turned it into the leading girls' school in the nation. This school was officially called the Harriet House School and popularly referred to as the Wang Lang School because of its location. The school prospered under her long, capable leadership and became an essential source of women teachers for government schools and mission schools in the Laos and Siam Missions. At the end of her career, Cole initiated the school's removal to its present location in 1921, where it is now called the Wattana Wittaya Academy. After a long period of illness, she officially retired in 1923 and died on 23 November 1950 in the United States.