Western North Pacific (WNP) tropical cyclone (TC) activity has experienced substantial structural reorganization during 1980–2024. Using CMA best-track data, HadISST, ERA5 reanalysis, and the Niño3.4 index, this study examines long-term changes in TC frequency, intensity composition, track-density redistribution, lifecycle-stage displacement, and associated SST–circulation linkages. Results show that annual TC frequency decreased significantly, whereas the proportion of super typhoons increased. Meanwhile, TC track density decreased over the tropical western Pacific but increased over parts of the subtropical WNP, leading to a significant poleward shift of the annual track centroid. Lifecycle decomposition further reveals strong intensity dependence. Severe tropical storms exhibit the most robust poleward signal, with significant northward shifts in lifetime maximum intensity and dissipation latitude, as well as enhanced genesis-to-dissipation displacement. Environmental analyses indicate that the poleward redistribution is associated with a La Niña-like Pacific SST pattern, western Pacific warming, northwestward displacement of the WNP subtropical high, and steering-flow anomalies favorable for poleward TC motion. These findings suggest that WNP TC risk and regional hazard exposure are being reshaped not only by changes in frequency and intensity composition, but also by spatial redistribution and lifecycle evolution.