Christian existentialism in the context of Existentialism

Søren Aabye Kierkegaard (/ˈsɒrən ˈkɪərkəɡɑːrd/ SORR-ən KEER-kə-gard, US also /-ɡɔːr/ -⁠gor; Danish: [ˈsɶːɐn ˈɔˀˌpyˀ ˈkʰiɐ̯kəˌkɒːˀ] ; 5 May 1813 – 11 November 1855) was a Danish theologian, philosopher, poet, social critic, and religious author who is widely considered to be the first existentialist philosopher. He wrote critical texts on organized religion, Christianity, morality, ethics, psychology, love, and the philosophy of religion, displaying a fondness for metaphor, irony, and parables. Much of his philosophical work deals with the issues of how one lives as a "single individual", highlighting the importance of authenticity, personal choice and commitment, and the duty to love. Kierkegaard prioritized concrete human reality over abstract thinking.

Kierkegaard's theological work focuses on Socratic Christian ethics, the institution of the Church, the differences among purely objective proofs of Christianity, the infinite qualitative distinction between man and God, and the individual's subjective relationship to the God-Man Jesus Christ, which came through faith. Much of his work deals with Christian love. He was extremely critical of the doctrine and practice of Christianity as a state-controlled religion (Caesaropapism) like the Church of Denmark. His psychological work explored the emotions and feelings of individuals when faced with life choices. Unlike Jean-Paul Sartre and the atheistic existentialism paradigm, Kierkegaard focused on Christian existentialism.

Danish philosophy has a long tradition as part of Western philosophy.

Perhaps the most influential Danish philosopher was Søren Kierkegaard, the creator of Christian existentialism, which inspired the philosophical movement of Existentialism. Kierkegaard had a few Danish followers, including Harald Høffding, who later in his life moved on to join the movement of positivism. Among Kierkegaard's other followers include Jean-Paul Sartre who was impressed with Kierkegaard's views on the individual, and Rollo May, who helped create humanistic psychology. Danish philosophy was also strongly influenced by French hermeneutics philosopher Paul Ricœur.

Atheistic existentialism is a kind of existentialism which strongly diverged from the Christian existential works of Søren Kierkegaard and developed within the context of an atheistic world view. The philosophies of Søren Kierkegaard and Friedrich Nietzsche provided existentialism's theoretical foundation in the 19th century, although their differing views on religion proved essential to the development of alternate types of existentialism. Atheistic existentialism was formally recognized after the 1943 publication of Being and Nothingness by Jean-Paul Sartre and Sartre later explicitly alluded to it in Existentialism is a Humanism in 1946.

Gabriel Honoré Marcel (7 December 1889 – 8 October 1973) was a French philosopher, playwright, music critic and leading Christian existentialist. The author of over a dozen books and at least thirty plays, Marcel's work focused on the modern individual's struggle in a technologically dehumanizing society. Though often regarded as the first French existentialist, he dissociated himself from figures such as Jean-Paul Sartre, preferring the term philosophy of existence or neo-Socrateanism to define his own thought. The Mystery of Being is a well-known two-volume work authored by Marcel.

Paul Johannes Tillich (/ˈtɪlɪk/; German: [ˈtɪlɪç]; August 20, 1886 – October 22, 1965) was a German and American Christian existentialist philosopher, religious socialist, and Lutheran theologian who was one of the most influential theologians of the twentieth century. Tillich taught at German universities before immigrating to the United States in 1933, where he taught at Union Theological Seminary, Harvard University, and the University of Chicago.

For the general public, Tillich wrote the well-received The Courage to Be (1952) and Dynamics of Faith (1957). His major three-volume Systematic Theology (1951–1963) was for theologians; in many points it was an answer to existentialist critique of Christianity.

Nikolai Alexandrovich Berdyaev (/bərˈdjɑːjɛf, -jɛv/; Russian: Никола́й Алекса́ндрович Бердя́ев; 18 March [O.S. 6 March] 1874 – 24 March 1948) was a Russian philosopher, theologian, and Christian existentialist who emphasized the existential spiritual significance of human freedom and the human person.