Research has demonstrated that Ce can significantly enhance both the mechanical properties and corrosion resistance of steel via two mechanisms: inclusion modification and microstructural regulation. For inclusion modification, Ce transforms detrimental Al 2 O 3 , MgO·Al 2 O 3 , and MnS inclusions into finely dispersed, stable Ce‐containing inclusions, thereby reducing inclusion size while enhancing distribution uniformity. Microstructurally, Ce inhibits P and As segregation at the grain boundaries, enhancing the boundary strength and optimizing the grain‐boundary structure. It also promotes grain refinement through heterogeneous nucleation and optimizes phase transformation by inducing intragranular ferrite formation and refining pearlite lamellae. This review systematically summarizes the modification and regulation mechanisms of Ce in steels, discusses their influence on mechanical properties and localized corrosion resistance, and provides theoretical guidance for the alloy design of high‐performance steels.