Malcolm X was famous due to his role as an outspoken advocate against racism and his alternative views to non-violent reactions to white aggression against black individuals. He was a key component of the popularity of the Black Power movement in the 1960's and 70's.
Malcolm X had a tumultuous childhood in which his father was murdered by a racist group called the Black Legion. He was jailed for six years when he was 21 years old, where he studied teachings of the Black Muslims, an extremist Black and Islamic group. He adopted their beliefs and actively taught them after his release from prison as the minister of Temple No. 7 in Harlem, New York. The beliefs contrasted Martin Luther King, Jr.'s anti-violent philosophy. It advocated the opposition of racism through any means necessary.
Malcolm X eventually left the Black Muslims, believing they were insincere as they did not fully support his beliefs and involvement in the civil rights movement. He abandoned some of the extremist views of the Black Muslims after learning that orthodox Muslim teachings did not entail the demonizing of whites, but taught the importance of equality between all ethnic groups. Adopting these new beliefs, he remained staunch in his anti-racist views and believed it was important that black people themselves fought against racial prejudice. He founded the socialist-based group called the Organization of Afro-American Unity in 1964, and was assassinated the following year by a member of the Black Muslims.