Sachs began lecturing in art history from 1916 to 1917 at Wellesley College where he had been appointed "Lecturer in Art." He was made an assistant professor in the Fine Arts department at Harvard in 1917. In 1922, he began his innovative course on museum curatorship titled "Fine Arts 15a: Museum Work and Museum Problems.", dealing with both curatorial and financial aspects of running a museum. He was appointed full professor in 1927. Sachs set about developing a program of museum education, developing students as what he termed the "connoisseur-scholar." One course was commonly called "the Print Course," which featured a seminar-style analysis of prints and drawings drawn largely from Sachs' own personal collection. From 1935 onward, he served regularly as chair of the Fine Arts department.