This paper offers a revisionary interpretation of Sartre's early views on human freedom. Sartre articulates a subtle account of a fundamental sense of human freedom as autonomy, in terms of human consciousness being both reasons-responsive and in a distinctive sense self-determining. The aspects of Sartre's theory of human freedom that underpin his early ethics are shown to be based on his phenomenological analysis of consciousness as, in its fundamental mode of self-presence, not an object in the world (Section 1). Sartre has a multi-level theory of the reasons-sensitivity of consciousness. At one level, consciousness's being alive to reasons is a matter of the affective perception of values and disvalues as features of phenomenal objects (Section 2). This part of his theory, a development of Scheler's, is, however, situated within a broader phenomenological analysis resulting in the claim that the ultimate reasons acknowledged by consciousness neither are nor justifiably could be values adequately presentable as intentional objects. Consciousness's ultimate reasons are, in this sense, not given by the world but by itself (Section 3). Section 4 reconstructs and assesses Sartre's argument that consciousness cannot rationally have an ultimate end other than self-transparent (‘authentic’) freedom itself.