Kubitschek was born into a very poor family in the countryside of Brazilian state Minas Gerais. His father, João César de Oliveira (1872 – 1905), who died when Juscelino was two years old, was a traveling salesman. He was raised by his mother, a schoolteacher named Júlia Kubitschek (née Kubíček; 1873 – 1971), of Czech descent.

Trained as a medical doctor, Kubitschek was elected to the Chamber of Deputies of Brazil from his home state in 1934. With the imposition of Getúlio Vargas' dictatorship in 1937, Kubitschek returned to practicing medicine. However, he was soon appointed mayor of Belo Horizonte in 1940. There, he idealized the project of an artificial lake (Pampulha Lake) to supply water to the city and also an architectural complex, with several buildings projected by renowned architect Oscar Niemeyer.

He was again elected to the National Congress of Brazil in 1945 and became governor of the state in 1950. In 1955, he ran for president with the slogan "fifty years of progress in five" and won.

He was sworn in on January 31, 1956 as President of what was then known as the Republic of the United States of Brazil.

Kubitschek's presidency was marked by a time of political optimism. He launched the "Plan of National Development", also known as the "Plano de metas (Goal's plan)", famous by the motto: "Fifty years of progress in five." The plan had 31 goals distributed in six large groups: energy, transports, food, base industries, education and the main goal, the construction of Brasilia. This plan searched to stimulate the diversification and expansion of the Brazilian economy, based on the industrial expansion and the integration of the national territory.

His government was marked by a time of political stability and maintenance of the democratic regime. Kubitschek used his outstanding political ability to reconciliate Brazilian society. He avoided any direct clash with his political adversaries, like the UDN, the main opposition party of the Kubitschek administration. He also gave political amnesty to the men that took part in the Jacareanga and Aragarças military revolts.

Although his main project was to develop the national industry, it was with the "Goals plan", launched in 1956, that there was a greater opening of the national economy for foreign capital. He exempted from taxes all the machines and industrial equipments imports, as well as the foreign capital. However, the exemption was made only if the foreign capital was associated with the national capital ("associated capital"). To amplify the internal market, he developed a generous credit policy.

He promoted the implementation of the automobile industry, with the coming of the automobile industries to Brazil, promoted the naval industry and the heavy industry, and the construction of hydro-electric power stations. With the exception of the hydro-electrical companies, Juscelino practically created no state owned companies. He also had a very progressive agenda on the Education front, but that was never carried out.

Kubitschek also cared a lot for the construction of the great transregional roads. He was criticized for focusing only in road construction and putting aside the rail transportation. Today, this decision is still controversial. Still, the construction of the roads helped the integration of the Amazonic region, together with the construction of Brasilia.

The economy boomed, but at considerable cost. His opponents alleged that he had brought "fifty years of inflation in five." Like many other Latin American currencies, the cruzeiro was repeatedly devalued. The country also went further into debt trying to pay for various ambitious projects, although such debts were very small compared to the tremendous rise of the external debt during the military dictatorship (1964 – 1985).

It has been said that Kubistchek had little time for accountants. Most of his grandiose plans as Mayor of Minas Gerais's elegant capital city, Belo Horizonte, and his later feats as State Governor were made possible only by virtue of his economic and administrative 'guru', an ethical, wise and hard working politician called Milton Campos.

Admittedly, from 1964 to 1980, Brazil grew steadily, and did so in compliance with a definite strategy and some of the country's best economists and planners were in office during this period. It was in the late 60s and early 70s that Brazil's current energy potential was fully developed. During most of this 20-year period, the generals that ruled Brazil were elected by indirect vote and in several instances congressional activities were severely restricted and often banned altogether.

The cost of dictatorships is all too evident: serious deterioration of institutional government and terrible breaches of human rights. It was during the military years that Brazil first became known for torture in prisons and human rights abuse.

Juscelino Kubitschek's administration, however, which came before the generals's, is seen as relatively peaceful and democratic. It is true that his inauguration was made possible only by a military coup, staged by General Henrique Lott in 1956, who deposed the legal stand-in President Carlos Luz, lest the latter would not hand in power to president-elect Kubitschek on the grounds of the scarcety of votes (Kubitschek, the winner on the 1956 presidential elections, received an unimpressive 36 per cent of the poll, and some legal haggling made a legal requirement that would put a mandatory constitutional prerequisite of 51 per cent). Still, Juscelino took office as planned and served a full term.

By the end of his term, the foreign debt had grown 1.5 billion dollars larger, getting to 3.8 billion dollars in the whole. The inflation and wealth inequality had grown larger, with the occurrence of strikes in the rural zone that expanded to the urban areas. However, the minimum wage from that time is still considered the largest in any moment of the Brazilian history.

Kubitschek ended his time in office with a growth of 80% in industrial production but with an inflation rate of 43%.

The idea of building a new capital in the center of the country was already idealized in the Brazilian constitution of 1891, 1934 and 1946, but it was only in 1956 that the construction began to take form. The works, led by the architects Lucio Costa and Oscar Niemeyer, started in the month of February 1957. More than 200 machines were put to work and 30.000 workers came from every part of the country, especially the northeast. The construction went on day and night, with the objective of finishing Brasília by 21 of April 1960, in a homage to the Inconfidência Mineira. The building was finished in 41 months, before the established date. As soon as it was inaugurated, Brasília was considered a masterpiece of modern urbanism and architecture. The New capital was to integrate all the Brazilian regions, create jobs and absorbe workforce from the Brazilian Northeast and to stimulate the economy of the Central west and North.

Kubitschek was not free from controversies. He was often accused of corruption. The accusation began at the time he was governor and intensified during his presidency. The building of Brasília was the main source of accusations. There were serious reasons to believe that people from Juscelino's political group had been favoured in the construction. Also, the Brazilian Pan-Air had the monopoly of people and goods transportation during the construction, another source of controversy.

During his office, the Brazilian press even said that he had the seventh greatest fortune in the world, a claim that was never proved. The candidate for the next presidency, Janio Quadros, used the accusations during his presidential campaign, promising to "sweep the corruption out of the country". Later, during the military regime, Juscelino would be questioned about the corruption allegations and about supposed ties with communist groups

Kubitschek was succeeded by Jânio Quadros in 1961. After the military took power in 1964, Kubitschek's political rights were suspended for 10 years. He went into self-imposed exile and stayed in numerous U.S. and European cities.

Despite all the problems, Kubitschek's presidency was seen as a time of optimism. The president was a cheerful and charismatic figure that exhaled confidence.

During the 50s, the Brazilian society was in transition from a rural to an urban society. With the industrial reforms, the emergence of the country as an industrial force could not be stopped anymore. This was also the time when household appliances started to enter people's lives. The middle class was now able to buy products that helped in their everyday tasks thanks to the infusion of foreign capital. The "American way of life" started to be implanted in the public's consciousness with radio shows, magazines and the newly arrived television.

Brazilian cinema was at its peak, with many movies being produced every year, mostly comedies called "Chanchadas". The prestige of the Brazilian cinema was such that in 1953 the movie "O Cangaceiro" received several foreign awards. Movie Companies like "Vera Cruz" and "Atlântida" were at their pinnacle.

Radio station audiences, especially for "Rádio Nacional", peaked. In 1958, João Gilberto published his record "Chega de Saudade", creating the Bossa Nova. Artists like Tom Jobin and Vinicius de Moraes came to be nationally and internationally known.

In sports, the national soccer team became 1958 FIFA World Cup champions in Sweden. Boxer Éder Jofre was world champion, as was the Brazilian basketball team in 1959, in Chile. Tennis player Maria Esther Bueno won both Wimbledon and US Open tournaments.

All these achievements infused a sense of victory and confidence in the future in the Brazilian public.

He returned to Brazil in 1967, but was killed in a car crash in 1976, near the city of Resende in the state of Rio de Janeiro. 350,000 mourners were present at his burial in Brasília. He is now buried in the Memorial JK, which was opened in 1981.

On April 26, 2000, former governor of Rio de Janeiro, Leonel Brizola, alleged that the ex-presidents of Brazil, João Goulart and Kubitschek, were assassinated as part of Operation Condor and requested the opening of investigations into their deaths. They were purported to have died respectively of a heart attack and a car accident.

The Presidente Juscelino Kubitschek International Airport of Brasília and the Juscelino Kubitschek bridge were named after him. There is also a luxurious hotel named Kubitschek Plaza located in that city. Many cities have things named after him, "JK" is a ubiquitous acroynm honoring the ex president, who is often seen by Brazilians as the "father of modern Brazil".

In 1980, his daughter Márcia (1942 – 2000) married Cuban-American ballet star Fernando Bujones. Márcia Kubitschek was elected to the National Congress of Brazil in 1987 and served as lieutenant governor of the Brazilian Federal District from 1991 to 1994.