Objective: Adults are at risk for unemployment following a moderate-severe traumatic brain injury (TBI). Less is known about employment patterns following mild TBI. This study aims to examine patterns of return to pre-injury job in adults following mild TBI over a 12-month post injury period, and to investigate factors associated with return to work. Methods: It is a prospective longitudinal study of 205 adults (aged ≥16 years at injury) identified as part of a larger population-based incidence study in the Waikato, New Zealand. In-person assessments were completed at baseline (within 14 days) and 1-, 6-, and 12-month post-injury. Results: A total of 159 (77.6%) adults returned to their pre-injury job at baseline and 185 (90.2%) returned within 12 months. Of those who did not return to their pre-injury job at baseline (n = 46), younger age at injury (≤30 years, p = .02) and poor overall neurocognitive functioning at 1-month (p = .02) was associated with non-return to pre-injury job at 12 months. Conclusion: In a sample of employed adults, the majority returned to their pre-injury job shortly after injury. Cognitive functioning and younger age at time of injury may be associated with delayed return to work. Interventions to support younger workers may facilitate their return to work.