Devices and methods for therapeutic photodynamic modulation of neural function in a human. One embodiment of a method in accordance with the technology includes administering a photosensitizer to a human, wherein the photosensitizer preferentially accumulates at nerves proximate a blood vessel compared to non-neural tissue of the blood vessel. The method can further include irradiating the photosensitizer using a radiation emitter positioned within the human, wherein the radiation has a wavelength that causes the photosensitizer to react and alter at least a portion of the nerves thereby providing a therapeutic reduction in sympathetic neural activity. Several embodiments of the technology are useful for disrupting renal nerves, such as renal denervation, for treating hypertension, diabetes, congestive heart failure, and other indications.