The performance limit of laser surface remelting (LSR) has long been constrained by the material's inherent and  passive heat-dissipation conditions. Here, an actively cooled laser surface remelting (AC-LSR) strategy is proposed and implemented to introduce thermal-boundary control into laser remelting. The core of this approach is an integrated active-cooling system, in which a copper heat sink is tightly coupled to the specimen through a high-thermal-conductivity interfacial material, enabling controllable heat extraction during melt-pool solidification. Using this AC-LSR platform, water cooling is identified as the most favorable thermal-boundary condition among the examined cooling media. Microstructural characterization and thermal simulation show that controlled heat extraction modifies the coupled response of temperature gradient and solidification rate, promotes grain refinement, enhances defect storage, and contributes to solute redistribution in the remelted layer. As a result, the water-cooled strategy increases the surface hardness by 72.6% and reduces the average friction coefficient at 22 ◦C and 750 ◦C from approximately 0.7 and 1.6 to below 0.4 and 1.5, respectively, while decreasing wear loss and improving wear resistance. The fundamental advancement of this study is that, under the present experimental conditions, active cooling is not merely an auxiliary heat-dissipation aid, but provides a tunable thermal-boundary condition capable of systematically regulating melt-pool solidification, microstructural evolution, and surface properties. This establishes a process–structure–property framework in which controlled thermal extraction can serve as an additional process dimension for surface strengthening.