Spinal circuits are essential for movement automaticity. The spinal cord not only executes and adjusts motor outputs by integrating information from multiple somatosensory channels but also undergoes lasting adaptation following repetitive practice in various motor tasks, even without brain inputs. However, the spinal mechanisms underlying these lasting sensorimotor adjustments remain unclear. Here, we establish a quantitative kinematic framework to characterize a spinal conditioning behavior, where spinal circuits, functionally isolated from the brain, learn to adapt motor output and retain the previously acquired behavior. Using kinematic analyses, mouse genetics, and virus-mediated circuit manipulations, we uncover that a class of dorsal spinal inhibitory neurons, Ptf1aON neurons, is crucial for this learning behavior. In-vivo high-density electrophysiological recordings in the spinal cord and optogenetics identification of Ptf1aON neurons in awake, behaving mice revealed a persistent, up-regulated activity of this population during learning. Further analysis reveals Ptf1aON neurons’ role in the selective modulation of Aδ/C second-order neurons to enhance the saliency of the modalities necessary for the learning behavior. Additionally, we characterize whether and how the spinal cord retains learned behavior by subjecting mice to a recall trial after a single training session. Interestingly, silencing of Ptf1aON neurons does not interfere with recalling behavior. However, selectively silencing or facilitating the activity of another class of ventral inhibitory neurons, Engrailed1ON neurons, flexibly disrupts or facilitates recalling conditioned behavior. Together, these results unveil the mechanisms regulating acquisition and retention of learned behavior which are mediated by two molecularly and spatially distinct spinal inhibitory populations.