The original U.S. embargo of Cuba was signed into law by President Kennedy. It has been altered, or more accurately intensified, over the years, eventually transforming into more than just an embargo.
The United States didn't want to impose an embargo on Cuba at first. It feared that this would give it a bad image in the rest of Latin America.
Eisenhower began the economic aggression towards Cuba. He began an embargo and ended Cuba's sugar quota. He also pressured American oil refineries refuse to process Russian oil, which led to their nationalization.
Before the embargo, Cuba and the U.S. had traded heavily. In 1958, the U.S. imported 75% of what Cuba exported, and 80% of Cuban imports came from the U.S.
Eisenhower had only prevented U.S. companies from exporting goods to Cuba. When Kennedy became President, he extended the embargo to include goods coming to the United States from Cuba.
This led Cuba to become economically dependent on the Soviet Union. Now, Cuba must import from other countries, which tremendously increases its importing costs.
So far, the embargo has not brought any change favorable to the United States, but has cost Cuba tens of billions of dollars.