Lavilla was a lawyer by profession. Lavilla was part of the Tacito group in the cabinet along with
Leopoldo Calvo Sotelo,
Andrés Reguera,
Eduardo Carriles,
Enrique de la Mata,
Marcelino Oreja and
Alfonso Osorio. when
Íñigo Cavero was appointed justice minister.
President of the Congress of Deputies and 23-F Lavilla was appointed senator in 1977 and was in office until 1978. He served as speaker of the Congress from 1979 to 1982 in the first legislature after the approval of the new
constitution. On 23 February 1981, members of the
Civil Guard led by
Antonio Tejero burst into the chamber in a failed
coup d'état. Lavilla faced Tejero saying that "in this chamber, the orders are given by the presidency. This is over. Vacate [the premises]." The colonel obeyed, and the deputies were able to occupy their seats after getting down. During the night of 23–24 February, he offered Tejero the members of the parliament board as hostages and asked that they free the
members of the government and the legislators, but Tejero rejected the move. During Lavilla's term the first investiture debate took place according to the new Constitution; 33 organic laws, 231 ordinary laws and 71 law decrees were approved, and the first failed
vote of confidence and a question of confidence were presented. an office which he held until his death in 2020. On 28 December 1995 he was appointed chairman of the Council's first section. On 8 February 1999 Lavilla took office as a permanent member of the
Royal Academy of Jurisprudence and Legislation and was its president between 2003 and 2012, being re-elected in 2008. In early 2014, he received a call from King
Juan Carlos I, who summoned him for a meeting where he explained that he was preparing
his abdication as monarch and asked him for advice. Years later, Lavilla revealed that he was in charge of preparing all the papers and the design of the succession process. He reached a preliminary conclusion: the abdication law should be very brief so as not to stir a debate in Congress. In addition, he was a member of the advisory committee of
FRIDE, a Madrid-based now defunct
think tank organization. ==Personal life and death==