The dynamics of transatlantic biomass burning aerosol transport remain poorly understood. Here we examine the vertical and zonal structure of smoke transport from North America across the Atlantic to Europe during the extreme 2023 Canadian wildfire season (May–September) using the Navy Aerosol Analysis and Prediction System Reanalysis (NAAPS-RA) and Moderate-Resolution Imaging Spectroradiometer fire and aerosol optical depth (AOD) products against a 2003–2022 baseline, complemented by model-derived plume injection heights for 2023. Over the Canadian source region, smoke AOD (AOD_smoke) at 550 nm was the highest in the 2003–2023 record in every month except August, exceeding the 2003–2022 mean by several-fold. The 0–2 km layer dominated at the source (78–93% over western Canada), but AOD_smoke fell sharply during transport and most smoke resided above 2 km: the 2–5 km layer became dominant across the Atlantic, and the extinction-weighted mean altitude rose from 1–2 to 2.5–4.3 km. A substantial fraction of fires injected smoke above 2 km, plausibly enabling this free-tropospheric transport. The monthly mean transport efficiency towards Europe was nonetheless low. Satellite AOD did not reproduce the zonal AOD_smoke pattern, suggesting that column-integrated satellite observations alone are probably insufficient to capture long-range smoke transport. Because monthly mean results may mask individual transport episodes, resolving such events should require dedicated analyses that combine models with remote and in situ observations.