When he graduated in June 1905, MacKaye was still unsure what career he should embark upon. During this time, he read Thomas Henry Huxley's 1877 work "Physiography: An Introduction to the Study of Nature"—a gift from his brother James, and a work that would prove influential in MacKaye's future regional planning. In October 1903, he enrolled in Harvard's newly established forestry school; he was the school's first student to graduate, in 1905. For the next five years, he alternated between teaching at Harvard's newly created forestry school near Petersham, Massachusetts, and working as a Forest Assistant with the Forest Service.