Marti was born in Havana, Cuba, then a colony of Spain. He came to dislike Spanish rule of his homeland at a young age, as well as developing a hatred of the institution of slavery which was still practiced in Cuba. At the age of 16, Marti was sentenced to 6 years of hard labor in the quarries for his political activity, after which was exiled to Spain, where he studied law and wrote articles on the wrongs of Spanish rule in Cuba.
After spending some time in France, he secretly returned to Cuba under an assumed name in 1877, but was unable to obtain any employment there. However, he was offered a job as professor of history and literature in Guatemala City.
In 1890, Martí moved to New York City serving as joint council there for Uruguay, Paraguay, and Argentina. He mobilized the Cuban exile community particularly in Tampa and Key West, Florida to revolution and independence from Spain, while lobbying to oppose US annexation of Cuba which some American politicians desired.
In 1894, he left with plans to land in Cuba to fight for the revolution, but was intercepted in Florida.
On March 25, 1895, Jose Marti published the Manifesto of Montecristi, proclaiming Cuban independence, an end to all legal distinctions between the races, friendship with Spaniards who did not oppose independence, and war with all who stood in the way of independence.
On April 11, 1895 Marti landed in Cuba with a force of rebel exiles, who hooked up with the rebel General Maximo Gomez y Baez. He was killed in battle with Spanish troops at Dos Rios, Cuba. Marti is buried in Cementerio Santa Efigenia in Santiago de Cuba.
He was strongly against US involvement in the Cuban War for Independance. The Spanish-American War began years after his death.
His best and most revered works were his books for children, "La Edad de Oro" (The Golden Age) his most widely read. One of his final poems, Versos sencillos was later put to music as Guantanamera, which has become Cuba's most famous patriotic song.