*Result*: Nonvolatile Electrical Programming of Valley Pseudospins in a Ferroelectric Van Der Waals Heterostructure.

*ABSTRACT Valley pseudospin, the third quantum degree of freedom for electrons in two‐dimensional crystals after charge and spin, exhibits two distinguishable states (K and −K) and serves as a versatile platform for information encoding, manipulation, and low‐power quantum technologies. However, most existing approaches rely on continuous external fields to transiently induce valley polarization, without stable K/−K occupation imbalance, fundamentally preventing nonvolatile valley‐based memory. Here, we demonstrate nonvolatile and electrically programmable control of valley pseudospins in a van der Waals heterostructure composed of monolayer MoSe2 and ferroelectric CuInP2S6 (CIPS). By integrating a gold micropillar electrode array with an electromechanical modulation scheme, localized strain gradients are introduced into the MoSe2/CIPS heterostructure, giving rise to flexoelectric fields that regulate Cu+ redistribution and enable robust, energy‐efficient control of excitonic properties. Magneto‐optical spectroscopy reveals that ferroelectric polarization‐induced interfacial fields enable reversible switching between spin‐allowed bright and spin‐forbidden dark trions, accompanied by a reversible Landé <italic>g</italic>‐factor tuning from −4.7 to −7.8. Under an external magnetic field, electrically driven valley polarization reaches 35.7%, exhibiting high contrast and long‐term retention. Furthermore, ASCII‐encoded valley polarization states demonstrate reliable nonvolatile information storage. This work establishes a versatile ferroelectric platform for reconfigurable valleytronic memory and programmable quantum photonics, paving the way toward scalable and energy‐efficient quantum information technologies. [ABSTRACT FROM AUTHOR]*