As president, he nationalized electric companies, created the National Commission for Free Textbooks (1959), and promoted the creation of prominent museums such as the Museum of Natural History and the National Museum of Anthropology in Mexico City. Declaring his political philosophy to be "left within the Constitution," López Mateos was the first left-wing politician to hold the presidency since Lázaro Cárdenas.
López Mateos was born in Atizapán de Zaragoza to Mariano Gerardo López y Sánchez Roman, a dentist, and Elena Mateos y Vega, a teacher. According to official records, a small town in the state of México, though at a young age his family moved to Mexico City upon his father's death. Nevertheless, there is a birth certificate and several testimonies archived at El Colegio de México that place his birth on 10 September 1909, in Patzicía, Guatemala.
In 1929, he graduated from the Scientific and Literary Institute of Toluca, where he was a delegate and student leader of the Socialist Labor Party.
Early in his career, he served as the private secretary to Col. Filiberto Gómez, the governor of the state of Mexico. In 1929, as a speaker he supported the presidential campaign of José Vasconcelos, an opposition candidate, against the presidential campaign of Pascual Ortiz Rubio. In 1934, he became the private secretary of the president of the Partido Nacional Revolucionario (PNR), Carlos Riva Palacio.
He filled a number of bureaucratic positions from then until 1941, when he met Isidro Fabela. Fabela helped him into a position as the director of the Literary Institute of Toluca after Fabela resigned the post to join the International Court of Justice. López Mateos became a senator of the state of Mexico in 1946. He served until 1952, when he became the Secretary of Labor, under President Adolfo Ruiz Cortines.
As Secretary of Labor, López Mateos managed well in difficult circumstances by defusing many labor strikes and pursuing a conciliatory policy. However, the teachers and railway workers movements "managed to endanger the stability of the regime."
In 1958, he was elected as president of Mexico as the candidate of the Institutional Revolutionary Party and served until 1964.
López Mateos was the first chairman of the Organization Committee of the 1968 Summer Olympics and called the meeting that led to the creation of the World Boxing Council.
Plagued with migraines during his adult life, he was diagnosed with several cerebral aneurysms, and, after several years in a coma, he died in 1969 of an aneurysm. His ex-wife Eva Sámano was buried next to him, in the Panteón Jardín in Mexico City, following her death in 1984. President Carlos Salinas de Gortari later had the remains of both moved to López Mateos's birthplace in Mexico State, and a monument erected to him there. Salinas's father Raúl Salinas Lozano had been a cabinet minister in López Mateos's government and passed over to be the next president of Mexico. The reburial of López Mateos's remains in the place now named Ciudad López Mateos in Mexico state rather than remaining in the national capital could be interpreted as political in various ways.
A wide range of social reforms were carried out during his presidency. Land reform was implemented vigorously, with 16 million hectares of land redistributed. The government also cleared and opened up new agricultural lands in the extreme south, which helped to reduce land tension in that part of the country. Public health campaigns were also launched to combat diseases such as polio, malaria, and tuberculosis. Typhus, smallpox, and yellow fever were eradicated, and malaria was significantly reduced.
Tackling poverty became one of the priorities of his government, and social welfare investments reached a historical peak of 19.2% of total investment. A number of social-welfare programs for the poor were set up, and the existing social-welfare programs were improved. Health care and pensions were increased, new hospitals and clinics were built, and the IMSS programme for rural Mexico was expanded. A social security institute was established, the Instituto de Seguridad y Servicios Sociales de los Trabajadores al Servicio del Estado (ISSSTE), to provide childcare, medical services, and other social services to workers, especially state employees. A 1959 amendment to the Social Security Law also brought part-time workers within the auspices of social security. He established the National Institute for the Protection of Children to provide medical services and other aid to children.
A food distribution system was established to provide affordable staples for poor Mexicans and a market for farm produce. The government entered the housing business on a large scale for the first time in Mexican history, with a major program being initiated to build low-cost housing in major industrial cities, with over 50,000 units of low-income housing constructed between 1958 and 1964. One of the largest housing developments in Mexico City housed 100,000 people and contained several nurseries, four clinics, and several schools.
In an effort to reduce illiteracy, the idea of adult education classes was revived, and a system of free and compulsory school textbooks was launched. In 1959, the National Commission of Free Textbooks (Comisión Nacional de Libros de Textos Gratuitos) was created. The textbook program was controversial. Education had become the largest single item in the federal budget by 1963, and there was a renewed emphasis on school construction. Almost every village was assisted in the construction of schools and provided with teachers and textbooks. Free student breakfasts for primary-school pupils were also restored.
An attempt was made at political liberalization, with an amendment to the constitution that altered the electoral procedures in the Chamber of Deputies by encouraging greater representation for opposition candidates in Congress. The electoral reform of 1963 introduced so-called "party deputies" (diputados del partido), in which opposition parties were granted five seats in the Chamber of Deputies if they received at least 2.5 percent of the national vote and one more seat for each additional 0.5 percent (up to 20 party deputies). In the 1964 elections, for instance, the Popular Socialist Party (PPS) won 10 seats, and the National Action Party (PAN) won 20. By giving opposition political parties a greater voice in government, the country, controlled by the Institutional Revolutionary Party, could have the appearance and greater legitimacy as a democracy.
The government succeeded in reducing labor unrest by setting up a National Commission for the Implementation of Profit Sharing which apportioned between 5% to 10% of each company's profits to organized labor. In 1960, Article 123 of the Constitution of 1917 was amended to ensure that government employees were protected by the minimum wage. Tight price controls and sharp increases in the minimum wage also ensured that the worker's real minimum wage index reached its highest level since the presidency of Lázaro Cárdenas. State intervention in the economy increased markedly between 1958 and 1964, with the government purchasing controlling stock in a number of foreign industries. The government also purchased the cinema industry, and it was decreed that ticket prices would be affordable for all.
His government achieved political and social stability by suppressing social movements. One example is the military operation of 1959 to end a conflict with the labor union of the railroad workers. During this operation, the strike was broken and Demetrio Vallejo, the leader of the railroad workers, was arrested.
López Mateos nationalized the electric industry in 1960.
López Mateos was succeeded as president by the conservative Gustavo Díaz Ordaz in 1964, also of the Institutional Revolutionary Party.
López Mateos welcomed US President John F. Kennedy to Mexico for a highly successful visit in July 1962. But Mexico's relationship with the United States changed by Mexico's friendly position towards the Fidel Castro in Cuba. The Chamizal conflict with United States was resolved and a majority of the Chamizal area was granted to Mexico.
In the last year of his presidency, López Mateos was visibly unwell. He looked worn-out and increasingly slim. On his very last months as president, a friend, Víctor Manuel Villegas, went to see him and remembers asking him how he was; he replied that he was "screwed up." It turned out that López Mateos had seven aneurysms. After finishing his presidential term, he served as head of the Olympic Committee, responsible for the organization of the Olympic Games in Mexico in 1968. He had to resign after a short period from his failing health. Manuel Velasco Suárez quotes him saying, "In every way, life has smiled at me. Now I must accept whatever may come."
Soon, he became an invalid. He was unable to move and after an emergency tracheotomy, he lost his voice. Enrique Krauze exclaimed on one of his books, "Gone was the voice of a once great orator."
López Mateos died in 1969 in Mexico City.