Studies have shown that supervisors’ autonomy supportive managerial style predicts static job performance and other positive organisational outcomes (Gagné & Deci, 2005). The present study extends these results by investigating the ways in which supervisors’ autonomy support affected job performance trajectories over a period of 5 months in a sample of 68 newly employed sport analysts. Multilevel modeling indicated that performance increases in a decelerated fashion over time. Perceived supervisors’ autonomy support significantly moderated the linear and quadratic performance trajectories. Thus, over time, the performance growth of employees who perceived their supervisors as supportive of their autonomy was steeper and decelerated at a slower rate. The implications are discussed in the light of autonomy support within Self‐Determination Theory (Deci & Ryan, 2000).