[1][2] He earned a Licentiate degree in Law at the University of Barcelona in 1950 and, three years later, in 1953, he joined the State Lawyers Corps, serving as such until 1965, when he was appointed Chief Administrative and Finance Officer of Renfe.

During the subsequent trial of the coup plotters, he had to intervene in the process to replace the president of the military court because he was unable to maintain the order of the sessions, which were especially tense and where the defendants caused disorder.

Faced with popular rejection of the low penalties for which they were convicted, Oliart ordered the prosecutor in the case to appeal the sentence on 10 June 1982.

[13] On 1 October 1982, the Supreme Court rejected the complaints filed by the insurgent military officers Jaime Milans del Bosch and Antonio Tejero against Oliart and Prime Minister Calvo-Sotelo, accusing the Defense Minister of attacking judicial independence for urging on behalf of the government recourse to the sentences that condemned them to prison.

[14] Oliart was also in charge of the reform of the Superior Center of Defense Information, naming on 23 May 1981 Lieutenant Colonel Emilio Alonso Manglano as its director with the mission of control and neutralization of any type of suspicious movement after the coup.

At that meeting, which lasted several hours, Manglano unveiled a coup d'état conspiracy that several military officials were preparing that was going to be especially bloody, and that was going to be executed on 27 October 1982, the day before the general election.

[24] He resigned on 6 July 2011 for "reasons of strict personal character and mature reflection", but after jumping to the controversy that he gave his son a public contract.

[29] A fan of writing, in 1997 he won the X Comillas Award for Biography, Autobiography and Memories for Against Oblivion ("Contra el olvido"), an autobiographical book, in which he recalls events that marked his life from childhood to adulthood.