Hurricane Fiona in late September 2022 was a large and destructive Category-4 Atlantic hurricane, with the wind gusts of about 180 km/h recorded at Arisaig of Nova Scotia. This storm was the most intense (and costly) extreme storm to hit Atlantic Canada on record, resulting in an issured loss of over 800 million Canadian dollar. A coupled wave-circulation model is used in this study to examine the storm-induced hydrodynamic changes and effects of wave-current interaction (WCI) during Hurricane Fiona. The coupled modelling system is based on the Regional Ocean Modeling System (ROMS) and the Simulating Waves Nearshore model (SWAN). Analysis of model results demonstrates very intense vertical mixing and currents generated by Hurricane Fiona in the surface mixed layer, both of which are biased to the right of the storm track. In addition to the strong wind forcing and large atmospheric pressure perturbations, the WCI plays a very important role in the hydrodynamic changes in the top ~80 m over the eastern Scotian Shelf and adjacent waters. Over the offshore deep waters (coastal waters) of the study region, the maximum significant wave heights (SWHs) reach up to 21 m (16 m), biased to the right of the storm track. The storm-induced near inertial currents are significantly stronger over the slope and deep waters compared to coastal and shelf waters.