[1][2] In 1931 Benítez began a career in education at the University of Puerto Rico that spanned four decades: he was associate professor of social and political sciences (1931–1942), chancellor of its main campus in Río Piedras (1942–1966) for nearly 30 years.

[2] In 1948, during his tenure as chancellor, the university's pro-independence student body invited nationalist leader Pedro Albizu Campos to the Río Piedras campus as a guest speaker.

[3] As chancellor, Benítez also attracted many distinguished scholars and artists who had left Spain after its civil war, including Nobel Prize-winning poet Juan Ramón Jiménez and Catalan cellist Pablo Casals.

He maintained an active role in numerous national and international organizations: he was a member of the United States National Commission for the United Nations Educational, Scientific, and Cultural Organization (UNESCO) from 1948 to 1954, and attended the UNESCO conventions in Paris, France (1950) and Havana, Cuba (1952); he was a member of the Constitutional Convention of Puerto Rico, for which he was drafted while attending an UNESCO meeting, and the chairman of the Drafting Committee on the Bill of Rights from 1951 to 1952.

The two fell out in 1957, however, when Muñoz declared his "loss of confidence" in Benítez and accused him of using his university position to build a rival political movement to his own Popular Democratic Party, or PDP.

[6] While in Congress he was a strong advocate of the current status of Puerto Rico, which he felt was preferable to statehood or independence.

[4] The road connecting the front gates of the Río Piedras campus to Highway 1, known as University Avenue, was renamed Paseo Jaime Benítez.

[12] In 2008, the Jaime Benítez National Park, at the easternmost part of the Condado Lagoon, was inaugurated in the presence of the then-governor Aníbal Acevedo Vilá and his wife Luisa Gándara who both arrived by kayak and sporting PPD-red-colored swimwear.

The project was developed by the Puerto Rico National Parks Company and the governor took the opportunity to attack his opponent, and eventual successor, Luis Fortuño for his financial dealings as then-resident commissioner, a post previously held by Benítez under the PPD.

[19] Jaime Benítez Rexach was interred at Santa Maria Magdalena de Pazzis Cemetery in San Juan, Puerto Rico.

[20] Since Benítez had been crucial in creating the Medical Sciences campus, the Society of Graduate Doctors of the UPR, on the occasion of the centenary of his birth, donated $20,000 for a mausoleum designed by Javier Toro, to be built on his tomb.

Based in the University of Puerto Rico at Arecibo, the primary goals of the foundation are to "collaborate in satisfying the socio-cultural, educational and economic needs of the institution.