In recent years, he enjoyed a revival as the inspiration of left-wing Latin American leaders such as Hugo Chavez, president of Venezuela, and Evo Morales, the Bolivian leader.
His struggles with Washington lead to a crippling political and economic blockade on the Caribbean island as well as an attempted invasion by Cuban exiles.
US-backed plots to remove him from power included one using exploding cigars and another that would have seen him poisoned with a diving suit contaminated with toxins.
According to one Cuban minister, more than 600 attempts were made on his life, but in the end nearly 50 years in power have meant that he has outlasted nine US presidents.
Fidel Alejandro Castro Ruz was born into a relatively wealthy Jesuit family in 1926 and graduated from Havana University as a lawyer.
It was there that he had become passionate about the lack of social justice in Cuba and, in 1953, he took up arms against the government of President Fulgencio Batista, leading an attack on the Moncada military barracks in Santiago de Cuba in which 80 men were killed.
Castro, and his brother Raul, were captured and jailed for 15 years, but released during an amnesty after two. He left Cuba and ended up in Mexico where he raised and trained fighters for the 26 July Movement which launched an invasion of Cuba in 1956.
|"There is not communism or Marxism in our idea. Our political philosophic is representative democracy and social justice in a well planned economy."|
The Batista government was overthrown and Castro was installed as prime minister.
Although Cuba's new rulers promised to return land to the people and defend the poor, Castro initially insisted that his philosophy was predominantly Cuban.
"There is not communism or Marxism in our idea," he said shortly after taking power.
"Our political philosophic is representative democracy and social justice in a well-planned economy."
But shortly after he took the reins, a perceived snub by Dwight Eisenhower, the US president, pushed him into the arms of the Soviet Union.
A range of pacts were signed between the Soviet Union and Cuba, securing large amounts of economic and military aid for the island.
The US then tried to topple Castro, launching an invasion at the Bay of Pigs in 1961. Cuban soldiers fought back the exiles that had been recruited by the US, killing many of them and capturing about 1,000.
Soon after, Castro declared Cuba to be a socialist nation for the first time.
Thousands of wealthy and middle class Cubans fled the country while the millions that remained became part of the left-wing experiment to create what Castro, and fellow revolutionary Ernesto Che Guevara, called "the new man".
The Bay of Pigs invasion also lead to a potentially even more dangerous confrontation in 1962.
Soviet nuclear missiles were placed on Cuba, ostensibly to protect it from further attacks by the US. Reconnaissance flights spotted the launch site on October 16 and during the next 12 days the world came the closest it ever has to nuclear war.
On October 28, Nikita Khrushchev, then Soviet leader, relented and announced that the missile site would be dismantled in return for a US guarantee that it would not invade Cuba.
Some would argue that the experiment worked. The free health care system is the envy of much of the world, the country's infant mortality rate also compares favourably with Western nations.
|Castro has experienced a revival|
as an icon of socialism [AFP]
Cuba also invested heavily in education and 98 per cent of the population are literate.
These successes have been held up as an example of how developing countries can succeed without relying on the US.
But much of this was paid for with Soviet money, the vast communist nation bought most of the country's sugar crop and brought desperately needed goods into Cuba despite the American embargo.
In fact, the end of the Soviet Union threatened to bring down his one-party state destroying the economy and bringing food shortages. Thousands of Cubans fled the country - taking to the sea in an attempt to reach Florida.
Opponents vilified Castro as a totalitarian ruler who carried out human rights abuses to crush political dissent.
In 2005, Amnesty International said the Cuban government was holding more than 70 people in poor conditions simply for disagreeing with the government.
In February, seven of those imprisoned were set free after human rights talks between Cuba and Spain.
The Cuban government insisted there are no political prisoners, only mercenaries financed by the US, criminals and "terrorists".
Castro ceded power temporarily to his younger brother Raul in July 2006, following emergency intestinal surgery. He is still recovering from an undisclosed illness.
He has not been seen in public since, but has appeared on television and writes in state newspapers.
In January 2007 Castro said in a letter published in several state-owned Cuban newspapers that he was "not physically able" to perform his public duties but would instead continue to write.
Although he did not indicate stepping down, Castro suggested a month earlier that he would not cling to power, nor stand in the way of a younger generation of Cuban leaders.
January's parliamentary elections, in which Cubans voted in uncontested polls, suggested a transition to a post-Castro government.
Fidel Castro's communist project has survived for so long that he is the only leader that most Cubans have ever known.
Only sketchy details are known about Castro's private life. He has married three times and has seven children.