<p>Single point incremental forming (SPIF) is a flexible technique for fabricating customized biomedical implants from hard-to-form alloys. However, the incremental nature of SPIF can cause surface topography, particularly in complex geometries like implants. Optimizing surface roughness is essential to balance implant biodegradability and cell attachment without increasing bacterial-induced degradation. This study introduces a novel tool path strategy for SPIF to enhance the surface quality and microstructural characteristics of patient-specific cranial implants. By using radial curvature segmentation and an adaptive highest curvature locus (HCL) approach, the method minimizes uneven deformation and typical surface topography. 3D optical surface profilometry showed that the adaptive tool path reduced roughness and large-scale waviness by promoting uniform deformation. Microstructural analysis revealed that the conventional tool path caused higher plastic deformation and grain refinement in titanium alloy implants, whereas the adaptive tool path resulted in lower dislocation density and residual stress. Conventional tool path resulted in low-angle grain boundary clusters within fragmented grains that also contain high-angle boundaries, potentially due to increased twinning under the higher levels of plastic strain. The adaptive tool path leads to more uniform deformation, resulting in lower dislocation density, in contrast to the conventional tool path, which exhibits more heterogeneous distribution of local misorientations. This optimized tool path strategy improves both surface quality and microstructural evolution of titanium alloy implants, which is crucial for their long-term stability and performance, offering significant improvements in the fabrication of customized biomedical implants.</p>