The synergy between school leadership and counseling services is increasingly viewed as central to effective and holistic student support, yet empirical evidence shows substantial variation across educational systems. This study aims to systematically compare global patterns of principal–counselor collaboration and to clarify how leadership models shape collaborative practices and student-related outcomes. Using a systematic literature review design, 67 empirical studies published between 2005 and 2025 were analyzed, comprising Asia (13), Africa (13), the Americas (13), Europe (13), and Australia (15). Data were examined through thematic analysis, enabling cross-continental comparisons of leadership orientation, organizational structure, and collaboration mechanisms. The findings identify five dominant collaboration models: strategic partnerships in the Americas, interdisciplinary teamwork in Europe, integrative–reflective collaboration in Australia, reactive hierarchical relationships in Africa, and normative–subordinative arrangements in Asia. These models reveal clear causal linkages between leadership orientation and student outcomes, particularly psychosocial well-being, preventive intervention capacity, and continuity of academic support. Leadership approaches characterized by shared decision-making, counselor integration into school governance, and data-informed collaboration consistently produce stronger and more sustainable student support systems, whereas hierarchical leadership structures constrain counseling impact and limit preventive effectiveness. This study contributes original value by offering a balanced cross-continental synthesis and an integrative analytical framework that connects leadership models, collaboration processes, and student outcomes. The findings advance comparative scholarship and provide a conceptual basis for developing evaluative tools and evidence-based policies to strengthen collaborative school leadership across diverse educational contexts.