Abstract: This study aimed to develop a healthier low-sodium salted Larimichthys crocea product by optimizing the curing process using KCl as a partial substitute for NaCl and to systematically evaluate its effects on product quality and flavor characteristics. A fuzzy mathematical comprehensive evaluation was employed to optimize the curing parameters. The optimized low-sodium treatment was compared with a conventional salt treatment using sensory evaluation, physicochemical analyses, gas chromatography–ion mobility spectrometry (GC–IMS), and an electronic nose (PEN3) to assess quality attributes and volatile flavor profiles. Salt concentration had the greatest influence on sensory quality, followed by KCl substitution ratio, pickling time, and pickling temperature. The optimal curing conditions were a brine-to-fish ratio of 1:1.2, pickling temperature of 4 ℃, 30% KCl substitution, 9% total salt concentration, and a pickling time of 24 h, achieving a sensory score of 90.50. Compared with conventional salt treatment, the optimized low-sodium treatment significantly reduced chloride content by 11.30% (5.83% vs. 6.57%, P < 0.05), while no significant differences were observed in moisture content or the texture of raw fish. After cooking, the low-sodium samples showed significantly higher adhesiveness and improved color stability. GC-IMS 53 volatile compounds, with esters and alcohols representing the predominant classes. The relative abundances of ethyl acetate and 2-methylthiophene increased, whereas ethyl isovalerate and ethyl butyrate decreased in the low-sodium treatment. Principal component analysis of the electronic nose data showed clear discrimination between treatments (discrimination index = 0.766), with significantly lower responses of the W1W and W5S sensors in the low-sodium group. Sensory evaluation further confirmed that partial substitution of NaCl with KCl did not significantly affect the overall sensory attributes of the product. Partial replacement of NaCl with 30% KCl effectively reduced sodium content while preserving the physicochemical properties, sensory quality, and characteristic flavor of salted L. crocea. These findings provide a scientific basis for developing healthier low-sodium salted aquatic products.