In this paper, a new energy-efficient level shifter capable of shifting an input signal from sub-threshold to above-threshold is presented. The new design combines the multi-threshold technique along with the internal supply feedback loop to guarantee a wide voltage conversion and energy-efficiency. It can convert a 276.8-mV input signal into a 1.2-V output signal across process corners with an operational frequency of 1-MHz, when implemented in a 65nm-LP technology. At the target design voltage of 0.3-V, the proposed circuit has a propagation delay of 13.4-ns, a static power dissipation of only 3.71-nw, and a total energy consumption per transition of 132.3-fJ for a 1-MHz input signal.