Purpose <p>Determine the association between self-reported physical function—measured using the PROMIS-10 Physical Function T-Score (PFT)—and outcomes up to 1 year following lumbar fusion.</p> Methods <p>This retrospective study focused on patients undergoing elective single or two level lumbar fusion. Patients were grouped by their electronically collected PFT score and classified as having below average function (BA), average function (A), or above average function (AA). Multivariate regression analyses were used to determine the associative relationships between the PFT and postoperative complications, as well as the Oswestry Disability Index (ODI) scores and pain reporting post fusion.</p> Results <p>307 patients were included in this study. Patients in the BA group had significantly worse ODI scores and reported higher levels of pain at all postoperative time points compared to the A and AA groups. Regressional analysis indicated the BA group was associated with an 80% decreased chance of being satisfied with their surgical outcomes when compared against the AA group (<i>p</i> = 0.004, 95%CI 0.07–0.080). The BA group was also associated with increased utilization of the emergency department within 30 days of the index procedure (<i>p</i> = 0.013, OR: 4.2; 95%CI 1.3–12.8).</p> Conclusions <p>Preoperative PROMIS-10 Physical Function T-scores were associated with post-operative outcomes following 1 or 2 level lumbar fusion. Patients self-reporting below average physical function were associated with increased pain and disability, lower satisfaction rates, and higher emergency department utilization than the other PFT groups. Therefore, the PFT subdomain score of the PROMIS-10 Global is associated with up to 1year outcomes following elective lumbar fusions, and may be able to be used in the future as a potential risk screening tool to identify patients at risk for poor postoperative outcomes.</p>