High‐valent iron active species (HVIAS)‐driven peroxymonosulfate (PMS) activation has emerged as a transformative approach in environmental remediation. This review systematically deciphers the mechanistic evolution and characterization advances of HVIAS generation: non‐radical‐dominated electron transfer pathways have been rigorously elucidated through in situ X‐ray absorption spectroscopy (XAS) and Mössbauer spectroscopy. In contaminant elimination, the HVIAS‐PMS system achieves 1‐2 orders of magnitude higher degradation kinetics than conventional radical‐based routes via targeted oxidation of electron‐rich moieties in antibiotics. To address real‐world wastewater complexity, 3D‐structured and 3D‐printed catalytic materials enhance HVIAS generation efficiency and stability through confinement effects and mass transport optimization. Nevertheless, critical challenges—including C‐F bond cleavage in PFAS, co‐existing matrix interference, and byproduct toxicity—demand urgent re‐evaluation for practical implementation. Future endeavors should prioritize smart‐responsive catalyst design, multi‐omics‐driven toxicity profiling, global byproduct database establishment, and cross‐scale integration of HVIAS‐PMS with renewable energy technologies. This perspective presents cutting‐edge advancements in HVIAS‐PMS systems, provides a multidimensional framework bridging fundamental research and applications for sustainable water decontamination, and discusses the limitations as well as prospects.