Metals and their compounds are core materials in energy catalysis; however, their performance is often constrained by conventional few-component systems, which typically feature single active sites and limited electronic-structure tunability. These limitations hinder precise regulation of complex reaction pathways and product selectivity. High-entropy strategies offer a promising route to overcome these challenges by enabling multi-element synergistic effects. Nevertheless, introducing multiple elements increases the tendency toward phase separation, making the controllable synthesis of single-phase, compositionally uniform high-entropy materials a key bottleneck for practical applications. To address this issue, this study develops a series of controllable synthesis strategies for high-entropy alloys, high-entropy ceramics, and two-dimensional (2D) high-entropy phosphorus trichalcogenides. Specifically, melt extraction is employed to fabricate high-entropy alloy fibers; pressureless sintering is used to synthesize dense high-entropy metal carbides; solid-state synthesis combined with ultrasonic exfoliation enables the production of 2D high-entropy phosphorus trichalcogenides; and a metal-organic framework-derived strategy is adopted to construct high-entropy metal oxides. These methods enable key advances in high-entropy material synthesis, particularly in compositional homogenization, structural densification, dimensional control, and precursor design. Moreover, the role of high-entropy engineering in regulating catalytic performance is systematically elucidated, highlighting the critical contributions of multicomponent synergy to basal-plane activation, optimization of metal—oxygen covalency, and enhancement of structural stability. Overall, this study aims to provide practical technical pathways and a theoretical framework for developing high-performance high-entropy materials through innovative synthesis strategies and in-depth mechanistic insights.