Traditional philosophical perspectives have often linked agency to human rationality and intentionality, but biological evidence suggests that agency predates human cognition and manifests in simpler life forms. This chapter explores agency as a biological phenomenon, examining its evolutionary origins and its role in shaping adaptive behavior. By investigating major evolutionary transitions this work frames agency as an integral driver of life’s increasing complexity. The study challenges conventional views by arguing that agency is not merely a product of evolution but an active force influencing evolutionary trajectories. Ultimately, this approach underscores the dynamic interplay between biological organization, environmental interactions, and the emergence of complex behaviors, offering a framework for understanding the evolution of agency beyond human cognition.