This paper studies the dynamics of workers’ on-the-job search behavior and its consequences in an equilibrium labor market. In a model with both directed search and learning about the match quality of firm-worker pairs, I highlight the job search target effect of learning: as a worker updates the evaluation of his current job, he adjusts his on-the-job search target, which results in a different job finding rate. This model generates a non-monotonic relation between the employment-to-employment transition rate and tenure, which provides a new explanation of the hump-shaped separation rate-tenure profile.