Trientine tetrahydrochloride (TETA-4HCl, Cuvrior®) is a copper chelating agent with the active moiety triethylenetetramine (trientine), developed by Orphalan, Inc. to address the unmet needs in the treatment of Wilson disease. The journey from bench to bedside builds upon the documented safety profile of trientine hydrochloride capsules developed initially to meet the needs of individuals intolerant to D-penicillamine (DPA). Trientine hydrochloride capsules are inherently unstable requiring strict cold chain storage conditions from production, transportation, and use at home by the patient. Trientine tetrahydrochloride has a distinctive, patent-protected unique polymorphic form, which permits the production at scale of film-coated scored tablets deemed room temperature stable for 36 months. Trientine tetrahydrochloride is supported by a well-characterized pharmacodynamic, pharmacokinetic, and metabolic profile demonstrating reliable and predictable dose linearity and dose proportionality kinetics. Trientine tetrahydrochloride is the only trientine formulation that has been compared with DPA in a prospective randomized clinical trial, demonstrating non-inferiority to DPA in adults with stable Wilson disease. On 28 April, 2022, the US Food and Drug Administration approved TETA-4HCl for use in adult patients with Wilson disease who are de-coppered and tolerant to DPA. Health authorities in multiple countries worldwide have approved TETA-4HCl for the treatment of adults and children aged 5 years or more who are intolerant to DPA including the European Union, UK, Saudi Arabia, Switzerland, Colombia, Australia, New Zealand, and China. This article aims to provide a comprehensive narrative review of the key milestones in the development of TETA-4HCl.