Fidel was born into the upper class of Cuban society in 1926. Early on at 13 he organized a workers strike at the sugar plantation his father owned.
He was well educated and went on to become a lawyer. Most of the cases he took were for the poor and was seldom paid which kept him less then wealthy. During his time as a lawyer he became more aware of the financial iniquities of the Cuban nation and the excessive control that American business held there.
In 1947 Castro moved into politics, joining the Cuban People's Party. The
main platform of this party was to rid the country of corruption and the policies that benefited American business while crapping on the majority of the Cuban people.
By 1952 he was the leader of the party and was expected to win the election of
the same year. Fulgencio Batista didn't like that idea so he took control of Cuba through the use of the armed forces.
In 1953 Fidel sparked the revolutionary spirit of Cuba with a failed attack on the Moncada Military barracks with 123 soldiers. He spent 2 years of his 15 year sentence for organizing and armed uprising in prison before Batista let him out under public pressure.
Castro went to Mexico to gather weapons and an army of 80 people. This movement called the July 26th Movement, named after the date of the initial attack on the barracks, returned to Cuba in 1956. They were promptly attacked by the Cuban army and reduced to 18 people. They regrouped and ran raids to rebuild their strength and supplies for a few months.
In a classic situation of the current dictator being an idiot, Fidel treated the peasants really well, while Batista slaughtered them in the attempt to find Fidel. Also the word spread that Castro's forces treated prisoners well so the Cuban army chose surrender and joined the revolution in large numbers. In this way, Batista grew weaker while increasing Castro's power.
Even with support from the United States, Batista couldn't win the fight and Fidel Castro took control of Cuba January 9th 1959.
The first policies he implemented were the distribution of land to the peasants, reduced rent for the poor and nationalized the phone company. He also promoted equality and abolished segregated facilities. Castro also closed down the mafia run night clubs and “insisted” that the people who ran them should leave Cuba.
Fidel promoted education to the point that 23% literacy rate before he was in power was brought up to that of places like Canada. The slogan for Cuba during this time was
"If you don't know, learn. If you know, teach." He also reworked the health care system and brought the infant mortality rate to levels better then parts of the United States.
He held the people responsible from Batista's government for the social crimes they committed against Cubans, and sentenced 600 of them to death.
A lot of these policies were not favored in the States, mostly because a lot of the distributed land was owned by Americans. United States gave the ultimatum that they would reduce trade with Cuba if these policies were not changed. That didn't work out as well as the Americans had planned and the USSR took up the trade when America denied it.
This royally pissed the Americans off especially when they are embroiled in the cold war at the time. The CIA decided to hire the Mafia to assassinate Fidel. Castro admits to 20 failed attempts on his life.