<p>Whether preoperative cervical curvature influences outcomes after uniportal posterior percutaneous endoscopic cervical foraminotomy (P-PECF) remains uncertain. This study evaluated whether global cervical alignment should guide candidacy or predict postoperative outcomes, particularly regarding sagittal alignment and instability. Fifty-seven patients undergoing P-PECF for cervical radiculopathy were retrospectively analyzed and stratified into lordotic or kyphotic groups based on preoperative C2–7 curvature. Clinical outcomes included visual analogue scale (VAS) scores for arm pain and the neck disability index (NDI). Radiographic assessments included C2–7 lordosis, cervical sagittal vertical alignment, C7 slope, flexion/extension range of motion, and disc height index. Multivariable regression identified predictors of change in C2–7 lordosis (ΔC2–7). This study provides phenotype-stratified outcomes with adjusted modeling, addressing a previously unresolved question of whether preoperative curvature should influence patient selection for P-PECF. Both groups demonstrated significant improvement in VAS-arm and NDI at one year (both <i>p</i> &lt; 0.001). Lordotic patients maintained alignment (17.38° → 15.27°, <i>p</i> = 0.19), whereas kyphotic patients restored toward lordosis (− 5.20° → +5.54°, <i>p</i> &lt; 0.001). No postoperative instability, conversion to fusion, or reoperation occurred. Preoperative curvature phenotype was not an independent predictor of ΔC2–7 (β = 1.23°, <i>p</i> = 0.757). Lower baseline lordosis (β = −0.54°/degree, <i>p</i> &lt; 0.001) and multilevel surgery (β = 5.52°, <i>p</i> = 0.024) were the strongest predictors of postoperative lordosis gain. P-PECF provides substantial symptom improvement and maintains or restores sagittal alignment across curvature phenotypes. Preoperative kyphosis alone should not be considered an absolute contraindication in appropriately selected patients. Baseline alignment and surgical extent more strongly determine postoperative sagittal change.</p>