A facile method for enhancing the interaction between pristine graphene and nonpolar rubber matrices was developed by preparing a new solution‐polymerized styrene‐butadiene‐p‐(2,2,2‐triphenylethyl)styrene (TPES) rubber (SBTR). SBTR macroradicals were formed by the thermal decomposition of a 1,1,1,2‐tetraphenylethane pendant. The macroradicals were successfully trapped by graphene through the formation of covalent bonds. This was confirmed by rotorless rheometer and X‐ray photoelectron spectroscopy measurements. The dispersion of graphene and interfacial interaction between graphene and the SBTR was significantly increased by increasing the TPES content in SBTR composites, as demonstrated by differential scanning calorimetry, scanning electron microscopy, rubber process analysis, and dynamic mechanical thermal analysis. The mechanical properties of the SBTR/GNS composites were significantly improved by the improved dispersion and the increased surface affinity of SBTR for graphene. The developed approach can be generally applied to the functionalization of other polymer matrices by copolymerizing TPES with other vinyl monomers for pristine graphene‐based composite materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44923.