Son of President Carlos Antonio López, was Colonel of the army at the age of 19, and Commander of the Paraguayan expeditionary army which approached currents in the campaign against the dictator Rosas, in 1846. In 1853 he traveled to Europe with diplomatic objectives, he visited England, France, Prussia, Sardinia. Hired armaments and shipbuilding, and managed the arrival in Paraguay technical English and a French colony. He met in France to Elisa Lynch, who would be his companion until his death. In 1856 was appointed Minister de Guerra, dedicated to organizing and arming a powerful national army. Appointed by his father President in secret contract, to his death, a Congress was confirmed in office in 1862.
To bordering issues resolved from the colony, joined the intermediation of the general López in the conflict of Brazil and Uruguay. In 1864 started the war against the Empire of Brazil; Subsequently the Paraguay declared war on Argentina and Uruguay joined the Triple Alliance. After some initial victories, the army and the people began to be decimated by the Allied troops in campaigns of Humaitá, Pikysyry, range, etc. The work, begun by his father, of the construction railway, arsenals, shipyards, cast iron, building renewal of the capital, etc., was also systematically destroyed by the invading army. Rumors of a conspiracy resulted in prosecution and death of some 400 citizens in 1868, during the war. He died in 1870 in Cerro Corá, surrounded by Brazilian troops, and with its demise the great war came to an end. His figure was reviled for five decades by the liberal historiography, and began to be claimed in the mid-1930s. The maximum national hero, is today considered although controversies about its historical role continue alive.