Abstract: A conductive hydrogel was fabricated through a one-pot free-radical polymerization of sodium carboxymethyl cellulose (CMCNa), acrylic acid (AA), and Fe³⁺. The interpenetrating and synergistic double cross-linked microstructure endows the hydrogel with excellent mechanical properties (tensile strength of 112.8 kPa and strain of 682.4%) and self-healing performance (performance recovers to 95% of the original within 72 h). The hydrogel also exhibits excellent ionic conductivity (1.75 S/m). The integrated mechanical properties and ionic conductivity enable the as-prepared hydrogel to demonstrate high sensitivity (a gauge factor (GF) of 2.86 at 600% strain), stability, and durability in sensor applications, allowing it to monitor both large-scale and subtle human motions. These properties make the hydrogel suitable for multifunctional wearable sensors. Overall, this research provides a simple and efficient synthesis route for preparing self-healing conductive hydrogels based on CMCNa.