The present disclosure is directed to a portable system and method for modulating targeted neural and non-neural tissue of a nervous system to block nerve conduction for the treatment of pain. A high-efficiency portable electrical stimulation system is provided that allows a user to carry the system and move around freely while continuously receiving therapy. The electronic control system is configured to deliver high-frequency electrical stimulation at a therapeutic level, for an intended duration (e.g., up to 24 hours or more) at a manageable and/or comfortable weight for a person, to the target nerve.