<p>Conventional thermoelastic models fail to capture the coupled size-dependent, memory-dependent, and high-frequency dynamics inherent in rotating viscoelastic nanostructures under multi-physics loads. To bridge this gap, this study introduces the first unified theoretical model that simultaneously incorporates Eringen’s nonlocal elasticity, Guyer–Krumhansl nonlocal heat conduction with a thermal length-scale parameter, the non-singular Caputo–Fabrizio fractional derivative, and a fractional Lord–Shulman/Moore–Gibson–Thompson thermoelastic framework. Applied to a finite rotating viscoelastic Kelvin–Voigt rod under a transverse magnetic field and a moving heat source, the unified formulation captures size-dependent mechanical behavior, nonlocal thermal diffusion, hereditary memory effects, finite thermal wave speed, Lorentz forces, and rotational dynamics in a single consistent framework. Results show that mechanical and thermal nonlocality dramatically smooth temperature gradients, lower peak temperatures, reduce displacement amplitudes, and virtually eliminate stress concentrations compared to classical local theories. The Caputo–Fabrizio derivative delivers smoother, more physically realistic memory-dependent responses than both the integer-order case and the traditional singular-kernel Caputo derivative. Rotation speed, magnetic field intensity, heat-source velocity, and fractional order strongly influence wave propagation and field distributions. The model provides an accurate predictive tool for rotating micro/nano rods in MEMS/NEMS, high-speed laser processing of viscoelastic nanostructures, magnetically controlled smart composites, aerospace components under combined thermal-rotational-electromagnetic loading, and advanced flexible electronics where precise management of size-dependent thermal stresses is critical. It establishes a robust, physically consistent foundation for designing and optimizing modern viscoelastic nanostructures subjected to extreme multi-physics environments.</p>