Climate warming is expected to weaken ocean circulation by suppressing deep-ocean eddy activity at mid and low latitudes. However, the future evolution of deep-ocean dynamics in the rapidly changing Arctic remains unclear. Here, we use 1-km-resolution simulations to show that the deep Arctic Ocean is projected to become substantially more energetic, particularly in the Eurasian Basin, in stark contrast to global mean trends. This increase in kinetic energy is driven primarily by intensified mesoscale eddy activity, fueled by enhanced lateral density gradients and available potential energy resulting from progressing Arctic Atlantification. Deep-ocean eddies account for more than half of the projected rise in Arctic total kinetic energy. The projected enhancement of eddy activity in both upper and deep layers implies that Arctic Atlantification could influence the Arctic Ocean and sea ice through dynamic pathways beyond simply supplying oceanic heat to the Arctic Ocean.