He was a member of the House of Representatives (1949–59) and of the Senate (1959–65), serving as Senate president (1963–65).
In 1965 Marcos, who was a prominent member of the Liberal Party founded by Roxas, broke with it after failing to get his party’s nomination for president.
Majority of politicians, including Grace Poe and Sonny Angara, have pointed out that his resignation should not be used as a shield from the injustices he made when he was justice secretary.
Aguirre later retaliated, stating that he left the Department of Justice with a better image, however, figures show otherwise, on April 6, 2018, the president appointed Menardo Guevarra as the new justice secretary, asking him to restore the destroyed image of the Department of Justice.
He then ran as the Nationalist Party candidate for president against the Liberal president, Diosdado Macapagal. Marcos won and was inaugurated as president on December 30, 1965.
In 1969 he was reelected, becoming the first Philippine president to serve a second term.
Marcos attended school in Manila and studied law in the late 1930s at the University of the Philippines, near that city.Opposed by political leaders—notably Benigno Aquino, Jr., who was jailed and held in detention for almost eight years—Marcos was also criticized by church leaders and others. Hoping to present an alternative to both Marcos and the increasingly powerful New People’s Army, Benigno Aquino, Jr., returned to Manila on August 21, 1983, only to be shot dead as he stepped off the airplane.In the provinces Maoist communists (New People’s Army) and Muslim separatists (notably of the Moro National Liberation Front) undertook guerrilla activities intended to bring down the central government. The assassination was seen as the work of the government and touched off massive antigovernment protests.During the impeachment trial of Renato Corona, he was tapped as one of several private prosecutors tasked to secure the Chief Justice's conviction.Aguirre was also a lawyer for then Davao Mayor Rodrigo Duterte, he served as the latter's chief legal counsel on the cases seeking to disqualify Duterte during the 2016 presidential campaign, as well as on cases linking the President to the Davao death squads.