 This research investigates laser-aided additive manufacturing, GELAM, of high strength steel using intrinsic tempering to form high fraction metal carbides, resulting in superior mechanical properties in as-built condition. Subsequent heat treatments further improve these properties by promoting grain and twin boundaries strengthening, precipitation strengthening, dislocation strengthening, twinning induced plasticity, TWIP, transformation induced plasticity, effects, and high work hardening rate during deformation. The findings suggest a potential way to develop AM customized materials by fully understanding and utilizing the intrinsic tempering effect. This article was authored by Chaolin Tan, Yuxiang Chu, Feiweng and others.