Spin manipulation is one of the most critical challenges to realize spin-based logic devices and spintronic circuits. Graphene has been heralded as an ideal material to achieve spin manipulation, but so far new paradigms and demonstrators are limited. Here we show that certain impurities such as fluorine adatoms, which locally break sublattice symmetry without the formation of strong magnetic moment, could result in a remarkable variability of spin transport characteristics. The impurity resonance level is found to be associated with a long-range sublattice pseudospin polarization, which by locally decoupling spin and pseudospin dynamics provokes a huge spin lifetime electron-hole asymmetry. In the dilute impurity limit, spin lifetimes could be tuned electrostatically from 100 ps to several nanoseconds, providing a protocol to chemically engineer an unprecedented spin device functionality.