Fidel Castro, from a wealthy Cuban landowner family, studied law at the University of Havana and became politicized by corruption and U.S. influence under Batista's dictatorship. His drive was anti-imperialism and nationalism, sparked by events like the 1940s Bogotazo and his failed 1953 Moncada attack.
Che Guevara, from an upper-middle-class Argentine family, trained as a doctor and traveled Latin America, witnessing poverty and U.S.-backed exploitation (e.g., in Guatemala's 1954 coup). This fueled his anti-capitalist ideology, leading him to join Castro after meeting in Mexico in 1955.
Their motivations centered on social justice, ending dictatorships, and resisting foreign dominance—not personal financial failure.
For more, see Wikipedia entries on their biographies.