We exploit distributed optoelectronic properties enabled by graphene Bragg gratings (GBGs) to realize a hybrid single-mode laser on silicon. This hybrid laser achieves single-mode, continuous-wave operation at 1540 nm with a remarkable side-mode suppression ratio of 48 dB, benefitting from the coupling of the GBGs. These results suggest that graphene thin films can be used as an essential and cost-saving component for hybrid photonic integration on silicon.