The paper is a novel extension of the Dialogical Self Theory (DST) to organizational psychology. In organizations there are rich conflicts and ambiguous situations in which joint meaning making is indispensable for future trajectories of the follower, the leader and the organization itself. This negotiation process is influenced by power imbalances within the organization, mostly between leader and follower. In their multiple emerging fields and their interrelatedness these agents have to find a way of neutralizing the tension of highly ambiguous situations in order to account for the discovery of commonly adaptive, future trajectories. I introduce the concept of the Existential-Humanistic Leadership style (EHL) that through the emergence of existential I-positions and sign-manifolds neutralizes previous power imbalances. The Trajectory Equifinality Approach (TEA) of Tatsuya Sato is used for elaboration of the ongoing dialogical processes. The TEA-modelling shows that an existential-humanistic leader tries to unite opposite trajectories within one dynamically adaptive system through phenomenological/democratic attunement towards the follower and through the assessment of follower's needs for development. These two conditions of EHL make it more likely that a leader externalizes existential I-positions which create local sign-worlds where leader and follower meet as human beings in absence of prior role asymmetry. Central concepts of existential psychology, DST and cultural semiosis are combined in a microgenetic and phenomenological research design. Based on the partnership model of Valsiner, Bibace, & LaPushin, a co-constructive interview guide has been created, in which a scenario-completion task is established and worked through with the participant. The Trajectory Equifinality Model of a football trainer is used for generalization of the generic structure of an existential-humanistic leader-system being a crucial condition for leading in and through curvilinearity.