Abstract <p>High-temperature creep deformation is often accompanied by microstructure evolution. However, aspects affecting the creep properties of materials such as substructure formation and kinetics of primary and secondary precipitates are not addressed by conventional models. In this work, a microstructure-dependent mean-field model is adapted to predict the non-classical creep deformation response of materials exhibiting solid solution hardening regimes. Numerical novelties include an improved stress-sensitive apparent activation volume for the dislocation glide velocity and a diffusion-based solid solution stress formulation through the internal stresses of the material. An Incoloy 800&#xa0;H experimental campaign to identify and validate the model combining creep tests and microstructural characterization techniques was performed. Additionally, ex situ thermokinetic simulations on Thermo-Calc^® PRISMA module were conducted to recover the physical evolution of precipitates during creep. The numerical predictions are in good agreement with the experimental results for low-stress and high-temperature loadings. The loss of predictability observed at high-stress levels is attributed to a creep mechanism transition. Exact stress and temperature ranges cannot be openly disclosed for confidentiality reasons.</p> Graphical Abstract <p></p>