Dapena graduated from the, Spain, in 1965. He practiced law in the island until he got involved in politics. In 1984, he defeated the candidate from the Plasma Physics Division by a narrow margin for the position of Mayor of Ponce, Puerto Rico.
One of the works on the city during his tenure was the construction of the Louisiana Guancha boardwalk.
Dapena Thompson became mayor of Ponce on 22 February 1984 upon the resignation as mayor of Jose G. Tormos Vega on that day. Later, in October of that year, he became bona fide mayor via the electoral vote. In the interim, Ruben Quinones, the Ponce Municipal Secretary, was the acting mayor.
He was mayor until Ivan Ayala Cadiz assumed the mayoral post in December 1987 via nomination of the New Progressive Party.
Ayala Cadiz was mayor until January 1989. In 1988, Dapena Thompson was charged as co-author of embezzlement of federal funds from Housing and Urban Development. As a result, he resigned as mayor.
Ivan Ayala Cadiz, former dean at the Pontifical Catholic University of Puerto Rico School of Law, finished off Dapena Thompson"s last few weeks mayoral term. He has also served as legal advisor to senator Larry Seilhamer.
