Hexagonal boron nitride nanoplatelets (BNNPs) can serve as two-dimensional (2D) fillers for elastomer nanocomposites due to their excellent and intriguing mechanical and thermal properties. Homogeneous and stable dispersion of BNNPs in elastomer is key to successful composite applications. Herein we propose a facile and easily industrialized approach for incorporating fully exfoliated BNNPs with hydroxyl functional groups into elastomer using the latex compounding method. The prepared BNNPs are highly dispersed in various solvents and their size of a few microns preserves their in-plane structure. The environmentally friendly, cost-effective, scalable preparation method proposed shows great potential for advancing the performance of elastomer nanocomposites. Specifically, the incorporation of BNNPs into the elastomer matrix remarkably improved the elastic modulus and tensile strength, even at low loadings; this was ascribed to the enhanced interfacial bonding of the BNNPs with the elastomer matrix. Moreover, well-dispersed BNNPs within the elastomer provided outstanding thermal conductivity and gas permeability.