In 1949, he returned to Harvard as a junior fellow of the Society of Fellows. In 1951, he became an associate professor; he then became Gordon McKay Professor of Applied Physics in 1957; Rumford Professor of Physics in 1974; and Gerhard Gade University Professor in 1980. In 1990 he retired from Harvard.
In addition, Bloembergen served as a visiting professor. From 1964 to 1965, Bloembergen was a visiting professor at the University of California, Berkeley. In 1996–1997, he was a visiting scientist at the college of optical sciences of the University of Arizona; he became a professor at Arizona in 2001.
Bloembergen was a member of the board of sponsors of the [http://www.thebulletin.org Bulletin of the Atomic Scientists] and honorary editor of the Journal of Nonlinear Optical Physics & Materials.