Patients with preoperative depressive symptoms may demonstrate inferior patient-reported outcomes (PROs). The effect of preoperative symptom duration (SD) on PROs in this population has not been well-studied. We aim to assess the influence of preoperative SD on PROs in patients with low mental health scores prior to minimally invasive transforaminal interbody fusion (MIS-TLIF). Patients who had undergone elective, primary MIS-TLIF with preoperative SF-12 MCS score below 45.6, a previously established threshold for depression, were selected. Patients were divided into matched lesser duration (LD; SD<365 days) and greater duration (GD; SD≥365 days) cohorts. PROs were collected preoperatively and at 6-week/12-week/6-month/1-year postoperative periods. PROs included PROMIS-PF/ODI/VAS back/VAS leg/SF-12 MCS. PROs were compared within and between groups. Rates of achievement of minimal clinically important difference (MCID) were compared between groups. One hundred twenty-two patients were included after matching cohorts. Patients in the LD cohort demonstrated improvement in PROMIS-PF at 12-weeks/6-month/1-year, and ODI/VAS back/VAS leg/SF-12 MCS at all postoperative periods (p≤0.024, all). Patients in the GD cohort demonstrated improvement in PROMIS-PF at 12-weeks/6-month/1-year, and ODI/VAS back/VAS leg/SF-12 MCS at all postoperative periods (p≤0.013, all). There were no differences in PROs or MCID achievement between cohorts at any period. Patients with preoperative depressive symptoms undergoing MIS-TLIF, regardless of duration of preoperative symptoms, demonstrated improvements in physical function, disability, pain, and mental health domains. Patients with greater duration of preoperative symptoms did not report inferior outcomes at any period. Rates of clinically important improvements in all domains were favorable and similar between cohorts.