Haizhou Bay (Jiangsu, eastern China) is a major land-sea transition zone, yet long-term sedimentary records of organic contaminants and their anthropogenic drivers remain poorly constrained, limiting a process-based understanding of regional pollution trajectories and their links to shifts in the energy mix. We quantified 16 priority polycyclic aromatic hydrocarbons (PAHs) and four sterols in four intertidal sediment cores using GC–MS. Spatial variability was evaluated across all cores, whereas centennial-scale (~150-year) temporal changes were interpreted primarily from the representative core HZ02, based on its published ²¹⁰Pbex–¹³⁷Cs chronology, for which PAH diagnostic ratios were also assessed. Source patterns were further constrained using bivariate correlations together with principal component analysis and hierarchical clustering. PAH concentrations decreased seaward, whereas sterols were strongly enriched near the Linhong River estuary. In the dated HZ02 record, low-molecular-weight PAHs dominated before 1950, followed by episodic increases in high-molecular-weight PAHs and sterols during the 1950s-1960s and the 1980s-1990s, and a decline in sterols in the early 2000s, consistent with reduced domestic wastewater-related inputs. Multivariate fingerprints indicate two dominant mixed sources: local inputs linked to agricultural biomass burning and household sewage, and an industrial–transport component associated with coal and petroleum combustion and traffic emissions. Contaminant histories covary with population density and energy consumption, supporting a transition from a pre-1950 biomass–sewage-dominated regime to a post-1950 industrial-transport mixture. These century-scale records provide a baseline for reconstructing coastal pollution histories and for evaluating how changes in energy use and emission controls shape organic contamination in eastern China.