Imprinting ferromagnetism to a graphene structure by substitution of carbon atoms with sulfur is reported. S-doped graphene (4.2 at%) shows strong ferromagnetic properties with saturation magnetization exceeding 5.5 emu g(-1) at 2 K, which is among the highest values reported for any sp-based system. The remarkable magnetic response is attributed to delocalization of electrons from sulfur injected into the graphene conduction band.