Pedogenesis entails profound changes in terrestrial phosphorus (P) dynamics yet means to understand how time- and climate-induced soil weathering impacts P-cycling over geologic timescales remains relatively limited to space-for-time substitution with multi-site chronosequences. We tested an alternative approach for evaluating terrestrial P dynamics described by the Walker-Syers model by measuring P pools in a ~ 450 ka loess–paleosol sequence. This vertical chronosequence reflected episodic pro-glacial loess deposition during multiple glaciations and interglacial soil development in central North America, and entailed a four-stage loess–paleosol sequence, initiated with the pre-Illinois Episode glaciation. Changes in P pools estimated by sequential fractionation aligned with the Walker-Syers P dynamic model for interglacial periods but not glacial periods, reflecting limited soil weathering in cooler and drier conditions. Total P decreased from 797 to 328 mg/kg with depth and was higher in paleosols than underlying loess parent materials. During glacial periods, primary P increased due to loess deposition and decreased during interglacial periods concomitantly with increased non-occluded and occluded secondary P pools, the extent of which reflected differences in weathering environments of paleoclimatic conditions and loess accumulation rates. That P fractions reflected the Walker-Syers model demonstrates that single-site vertical chronosequences have potential for evaluating long-term soil P dynamics.