<p>With the increasing demand for high reliability and extended service life of critical components in modern manufacturing, laser cladding (LC) has attracted considerable attention as an efficient surface strengthening and repair technology. In practical engineering applications, a large number of high-value steel components serve long-term in a carburized state, in which surface properties dominate their service behavior, making in-situ remanufacturing studies of carburized components highly relevant for engineering applications. In this study, Ni60 coatings were fabricated by laser cladding on both carburized and non-carburized 8CrMoV steel substrates, and the effects of the carburized layer on microstructural evolution, crack behavior, and mechanical properties were systematically investigated through a comparative analysis. The results show that the coatings were mainly composed of γ-(Ni, Fe), M₇C₃ (M = Cr, Fe, Ni), FeNi₃, Ni₃Si, CrB, and Cr₅B₃ phases, while the presence of the carburized layer did not alter the phase constitution of the coatings. Nickel-rich dendrites grew perpendicular to the coating–substrate interface. Preferential precipitation of chromium borides promoted the epitaxial growth of chromium carbides, resulting in a radially distributed, irregularly banded microstructure. The elevated carbon content in the carburized substrate promoted the precipitation of carbides and borides, leading to an increase in local hardness while simultaneously influencing crack initiation behavior. The coating deposited on the carburized substrate exhibited a significantly higher microhardness (327.7 ± 7.8 HV_0.2) compared with that on the non-carburized substrate (291.2 ± 6.3 HV_0.2), together with a lower coefficient of friction and more stable wear behavior. LC Ni60 coatings exhibited favorable microstructural stability, mechanical properties, and tribological behavior on carburized steel substrates. This makes them suitable for the in situ remanufacturing and life extension of carburized components.</p>