His father, José María Benegas Echeverría, was an exiled Basque Nationalist politician, who fled Spain in 1939 following the victory of Francisco Franco in the Spanish Civil War.

Benegas moved to Spain in 1955 and studied in the Jesuit College before qualifying as a lawyer at the University of Valladolid in 1971.

Despite the PSOE increasing their vote and more than doubling their number of seats from 9 to 19, he was unsuccessful in his bid to become Lehendakari or President of the autonomous government of the Basque Country.

As a result, the PNV lacked sufficient support to govern and was forced to call early elections in 1986 at which Benegas was again the candidate for Basque President.

His son is the Spanish musician and songwriter Pablo Benegas, guitarist in the group La Oreja de Van Gogh.