Triage is a high-stakes clinical function in emergency medicine, requiring rapid risk assessment, sound decision-making under uncertainty, and advanced communication within severe time constraints. This chapter examines the evolution of the “triage professional” from early physician-centered models to the contemporary international consensus that positions triage as an advanced nursing role. It defines the triage nurse’s core competency domains, holistic yet focused assessment, interpretation of vital signs in context, recognition of danger signs, conflict management, documentation, and operational autonomy within protocols, and outlines evidence-based prerequisites for role assignment. The chapter then addresses training design and sustainability, including structured programs, supervised preceptorship, skill decay, and the value of refresher training, audits, and individualized feedback to reduce inter-operator variability. Finally, the chapter integrates human factors and standardization, highlighting how cognitive and demographic biases can affect triage decisions and why objective, auditable frameworks should structure, rather than replace, professional judgment.