Sea ice is a heterogeneous, evolving mosaic of individual floes, varying in spatial scales from meters to tens of kilometers. Both the internal dynamics of the floe mosaic (floe‐floe interactions), and the evolution of floes under ocean and atmospheric forcing (floe‐flow interactions), determine the exchange of heat, momentum, and tracers between the lower atmosphere and upper ocean. Climate models do not represent either of these highly variable interactions. We use a novel, high‐resolution, discrete element modeling framework to examine ice‐ocean boundary layer (IOBL) turbulence within a domain approximately the size of a climate model grid. We show floe‐scale effects could cause a marked increase in the production of fine‐scale three‐dimensional turbulence in the IOBL relative to continuum model approaches, and provide a method of representing that turbulence using bulk parameters related to the spatial variance of the ice and ocean: the floe size distribution and the ocean kinetic energy spectrum. Plain Language Summary Sea ice is a complex broken mosaic of individual pieces, called floes. These floes control how heat and momentum move between the atmosphere and ocean. But these floes interact with each other as well as with the upper ocean and lower atmosphere, and this means that these exchanges can be complexly related to both types of processes: floe‐floe and floe‐flow. Using experiments that explicitly evolve sea ice floes interacting with each other and the upper ocean, we develop a formulation for how momentum is transferred between the ice and ocean as a function of simple parameters of the ice‐ocean system that may be available to climate models. Key Points Discrete element model results show floe‐size‐dependent ice‐ocean boundary layer (IOBL) stress‐driven turbulence IOBL turbulence is driven both by floe collisional velocity and by floe‐scale ocean variability We present a framework for a scale‐aware parameterization of IOBL turbulence using bulk parameters