Jean-Paul Sartre's life exemplified existential philosophy through his experiences during World War II and his involvement in political movements. Growing up in a middle-class family, Sartre developed a keen sense of individuality and freedom. His time as a soldier and subsequent encounters with Nazism sparked his philosophical inquiries into the absurdity of existence. Sartre's relationships, particularly with Simone de Beauvoir, deepened his understanding of human relationships and subjectivity. His literary works, such as "Being and Nothingness," encapsulate his exploration of freedom, choice, and the burden of existence, influencing generations of thinkers.