Sanborn earned her first money by writing, at the age of 11, and at 17 engaged in teaching. She taught English literature in several places, and was a professor at Smith College in that subject for several years, resigning in 1886 in order to follow literary pursuits in New York City. She was a teacher of elocution at Packer Institute in Brooklyn.
She lectured in public on literary history and allied subjects, and wrote on education. Her lecturing career began in the drawing room of her friend Anne Lynch Botta and later she gave talks for clubs and schools on current literature. She lectured on literary topics for 20 years. For several years she was a newspaper correspondent in New York City. She also edited calendars and holiday books.