 She obtained another master's degree in history from Radcliffe College, Harvard University in 1920, and a Ph.D. from Columbia University in 1923.Alzona was the first Filipino woman to have obtained a Ph.D.

Alzona returned to the Philippines in 1923 and joined the faculty of the Department of History, of the original Manila campus of the University of the Philippines, which was later moved to the University of the Philippines Diliman.Even as American women won the right to vote in 1920, women in the Philippines, then an American colony, were not accorded the same right.