Graphene-embedded carbon nanofibers (GCNFs) were developed as a new counter electrode nanomaterial for high efficiency dye-sensitized solar cells (DSCs). GCNFs were produced by electrospinning polyacrylonitrile (PAN) with graphene nanoplatelets followed by stabilization and carbonization. GCNFs decorated with surface-attached platinum nanoneedles (GCNFs-PtNNs) were subsequently prepared by a redox reaction and then deposited onto fluorine doped tin oxide (FTO) glass to make a counter electrode for DSCs. Graphene inside the carbon nanofibers and Pt nanoneedles on the surface demonstrated a synergistic effect to improve the DSC performance. Compared to DSCs with conventional planar Pt counter electrodes, the DSCs with GCNFs-PtNNs significantly improved the energy conversion efficiency from similar to 8.63% to similar to 9.70% using a mask under AM1.5 illumination. This is the highest conversion efficiency so far with a carbon nanofiber based counter electrode.