Objective In response to the clinical needs for personalized wrist orthoses, a topological optimization design method is proposed to achieve an integrated macro- and micro-structural optimization of a personalized, lightweight, and comfortable wrist orthosis. Methods A finite element analysis model of the wrist orthosis and the upper limb's biomechanical environment was established to quantify the effects of the orthosis geometry on fixation performance and comfort during daily activities. A multi-condition topological optimization and microstructure design approach was employed to optimize the non-load-bearing areas of the orthosis. The orthosis was manufactured using 3D-printed polyetheretherketone, and the design's feasibility was validated. Results While maintaining mechanical strength, the weight of the 3D-printed PEEK orthosis was reduced by 28% compared to traditional orthoses. Both the pressure values at the skin-contact interface and the results of a subjective questionnaire indicated that test subjects experienced a high level of comfort wearing the orthosis. Conclusions The orthosis design achieved personalization, lightweight structure, and high comfort while ensuring mechanical strength and fixation performance.