In 1807, Willard left Berlin and briefly worked in Westfield, Massachusetts, before accepting a job offer at a female academy in Middlebury, Vermont. She held the position of principal at the Middlebury Female Seminary from 1807 to 1809. She was unimpressed by the material taught there and opened a boarding school for women in 1814, in her own home. She was inspired by the subjects her nephew, John Willard, was learning at Middlebury College and strove to improve the curriculum that was taught at girls' schools. Willard believed that women could master topics like mathematics and philosophy rather than just subjects taught at finishing schools. This passion for women's education led her to fight for the first women's school for higher education.