Long COVID has widespread and long-lasting multisystemic impacts on patients' bodies, cognition, and daily functioning, including the ability to work. Longitudinal studies are important in investigating the expected timelines along the course of recovery. This mixed cross-sectional/longitudinal study examines how symptoms (cognitive and noncognitive) and objective cognitive function evolve in post-COVID-19 patients (n = 187) compared to noninfected controls (n = 207). Participants completed a questionnaire about their COVID-19 experience and cognitive tasks at baseline and again at 2-3 follow-ups during a 9-month period. While some noncognitive symptoms improved over time (ds = 0.34-0.87), cognitive symptoms and neurological symptoms, as well as memory function assessed with objective cognitive assessments, remained unimproved (nonsignificant change over time). Neurological symptoms predicted both cognitive symptoms and cognitive impairment across time. Our finding suggested that people with past COVID-19 infection did not experience improvement in cognitive function over time, at least for the duration of this 9-month longitudinal study.