Background and Purpose This prospective longitudinal study identifies early diffusion tensor imaging biomarkers of mild traumatic brain injury that significantly relate to outcomes at 1 year following injury. Materials and Methods DTI was performed on 39 mild traumatic brain injury subjects within 16 days of injury and 40 controls; 26 mild traumatic brain injury subjects returned for follow-up at 1 year. We identified subject-specific regions of abnormally high and low fractional anisotropy, and calculated mean fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity across all white matter voxels brain-wide, and across each of several white matter regions. Assessment of cognitive performance and symptom burden was performed at 1 year. Results Significant associations of brain-wide DTI measures and outcomes included: mean radial diffusivity and mean diffusivity with memory; mean fractional anisotropy, radial diffusivity and mean diffusivity with health-related quality of life. Significant differences in outcomes were found between subjects with and without abnormally high fractional anisotropy for the following white matter regions and outcome measures: left frontal lobe and left temporal lobe with attention at 1 year, left and right cerebelli with somatic post-concussion symptoms at 1 year, and right thalamus with emotional post-concussion symptoms at 1 year. Conclusion Individualized assessment of DTI abnormalities significantly relates to long-term outcomes in mild traumatic brain injury. Abnormally high fractional anisotropy is significantly associated with better outcomes, and might represent an imaging correlate of post-injury compensatory processes.