Heideggerians regarded Søren Kierkegaard as, by far, the greatest philosophical contributor to Heidegger's own existentialist concepts.
Heidegger's concepts of anxiety (Angst) and mortality draw on Kierkegaard and are indebted to the way in which the latter lays out the importance of our subjective relation to truth, our existence in the face of death, the temporality of existence, and the importance of passionate affirmation of one's individual being-in-the-world.

Patricia J. Huntington claims that Heidegger's book Being and Time continued Kierkegaard's existential goal.
Nevertheless, she argues that Heidegger began to distance himself from any existentialist thought.

Calvin Shrag argues Heidegger's early relationship with Kierkegaard as:
Kierkegaard is primarily concerned with existence as it is experienced in man's concrete ethico-religious situation.
Heidegger is interested in deriving an ontological analysis of man.
But as Heidegger's ontological and existentialist descriptions can arise only from ontic and existential experience, so Kierkegaard's ontic and existential elucidations express an implicit ontology.
Heideggerians regarded Søren Kierkegaard as, by far, the greatest philosophical contributor to Heidegger's own existentialist concepts. Heidegger's concepts of anxiety (Angst) and mortality draw on Kierkegaard and are indebted to the way in which the latter lays out the importance of our subjective relation to truth, our existence in the face of death, the temporality of existence, and the importance of passionate affirmation of one's individual being-in-the-world.
Patricia J. Huntington claims that Heidegger's book Being and Time continued Kierkegaard's existential goal. Nevertheless, she argues that Heidegger began to distance himself from any existentialist thought.
Calvin Shrag argues Heidegger's early relationship with Kierkegaard as:
Kierkegaard is primarily concerned with existence as it is experienced in man's concrete ethico-religious situation. Heidegger is interested in deriving an ontological analysis of man. But as Heidegger's ontological and existentialist descriptions can arise only from ontic and existential experience, so Kierkegaard's ontic and existential elucidations express an implicit ontology.
Martin Heidegger