Background Limited spine literature has studied the strength of association of mental health with other outcomes at time of survey collection. We aim to evaluate the degree to which mental health correlates with outcomes in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) at several postoperative periods. Methods Patients having undergone elective MIS-TLIF were searched within a retrospective single-surgeon database. Five hundred eighty-five patients were included. Patient-reported outcomes (PROs) including Patient-Reported Outcome Measurement Information System Physical Function (PROMIS PF), 12-item Short Form Physical Component Score (SF-12 PCS) and Mental Component Score (SF-12 MCS), Patient Health Questionnaire-9 (PHQ-9), Visual Analog Scale (VAS) back and leg pain, and Oswestry Disability Index (ODI) scores were collected preoperatively and at 6-week, 12-week, 6-month, 1-year, and 2-year periods. Pearson’s correlation tests were used to evaluate the association between both SF-12 MCS and PHQ-9 scores to other PROs at each period. Results SF-12 MCS correlated with PROMIS PF (| r |= 0.308–0.531), SF-12 PCS (| r |= 0.207–0.328), VAS back (| r |= 0.279–0.474), VAS leg (| r |= 0.178–0.395), and ODI (| r |= 0.450–0.538) at all time points ( P  ≤ 0.021, all) except for preoperative SF-12 PCS and 1-year VAS leg. PHQ-9 correlated with PROMIS PF (| r |= 0.366–0.701), SF-12 PCS (| r |= 0.305–0.568), VAS back (| r |= 0.362–0.714), VAS leg (| r |= 0.319–0.694), and ODI (| r |= 0.613–0.784) at all periods ( P  < 0.001, all). Conclusion Poor mental health scores were correlated with lower physical function, elevated pain scores, and higher disability. PHQ-9 scores demonstrated stronger correlation in all relationships compared to SF-12 MCS. Optimization of patient mental health may lead to improved patient perception regarding function, pain, and disability following MIS-TLIF.