Elemental partitioning across the precipitate/matrix interface controls the kinetics of precipitate evolution, during growth and coarsening. We present the first comprehensive analysis of evolutions of both the aspects of microstructure, i.e., the size (of nano-scale, ordered coherent γ′ precipitates) as well as the lattice misfit (between γ and γ′), in light of elemental partitioning, applied to a Ni-based superalloy, HAYNES 282. In this work, eexperimental analyses by atom-probe tomography, transmission electron microscopy, and x-ray diffraction are combined with thermo-kinetic modelling using ThermoCalc® and TC-PRISMA®. The current study has isolated the growth and the coarsening regimes, analyzed the respective kinetics and identified their individual rate controlling processes, for the first time. While Cr and Ti are found to be the rate controlling in the growth regime due to their larger amount of partitioning need, Mo becomes rate controlling in the coarsening regime. From the APT data, it is however clear that diffusion across the interface remains slowest for Mo, both in the growth and the coarsening stages. For the coarsening kinetics, unlike most of the recent literature, we have used the thermodynamic parameter corresponding to the non-dilute, non-ideal γ solid solution phase in the modified LSW rate equation. This approach provides a much realistic prediction, as Ni-based superalloys show significant deviation from ideality. Constrained misfit has been found to be positive and found to decrease with ageing time in the present alloy. Elemental partitioning explained quantitatively the variation in the lattice parameters and the misfit.