Actuators based on stimulus-responsive soft materials have attracted widespread attention due to their significant advantages in flexibility and structural adaptability over traditional rigid actuators. However, the development of fast-actuating, mechanical robust and self-healing actuators without compromising flexibility remains an ongoing challenge. Here, this study presents a photo-responsive flexible actuator by incorporating core–shell liquid metal nano-assemblies into a polyurethane matrix to construct a dynamic supramolecular interface. The nano-assemblies are endowed with adaptive characteristics to external loading, being expected to dissipate energy via the reversible reconstruction of hydrogen bonding and deformation of nano-assemblies. The obtained composites exhibit excellent mechanical strength (31 MPa), low modulus (2.02 MPa), high stretchability (1563.95%), autonomous self-healing (92.5%), and NIR-responsive actuation properties. Furthermore, the combination of high cohesive energy but fluxible nano-liquid metal core, and strong dynamic interface not only achieves the balance of high tensile strength and high flexibility but also endows the actuators with outstanding notch-resistant performance (fracture energy≈58.8 kJ m−2) through multiphase energy dissipation. This work provides a promising strategy for developing soft yet tough self-healing materials in the fields of flexible robotics and artificial muscles.