The goal of this longitudinal study was to examine how three dimensions of self-reported work performance, including task proficiency, adaptivity, and proactivity, changed between December 2019 and September 2020 in Germany. Based on event system and transition theories, we expected work performance to decline due to the “lockdown” between early April and early May 2020, and to subsequently increase when restrictions were eased between early May and early September 2020. Additionally, we hypothesized that high levels of core self-evaluations (i.e., employees’ fundamental evaluations about themselves) buffer the decline and strengthen the recovery in work performance. Data were collected from N = 591 full-time employees across eight measurement points. Results based on discontinuous latent growth curve modeling largely supported the expected trajectories in work performance. Moreover, core self-evaluations positively predicted the levels of work performance, as well as the slopes indicating recovery in task proficiency and adaptivity, but not proactivity.