Achieving ideal metal/semiconductor junctions remains a critical challenge in advancing 2D electronics. While current approaches often rely on clean van der Waals contact interfaces to mitigate Fermi‐level pinning, they offer limited tunability in achieving precise energy level alignment with 2D semiconductors. In this work, a wide range of work function modulation in copper sulfide (Cu2−xS, 0 ≤ X < 1) electrode materials is proposed that can be achieved through an air‐ambient sulfurization process. Depending on the concentration of sulfur atoms, the Cu2−xS electrode showed considerable modulation in work function from 5.10 to 4.15 eV (ΔΦ = 950 meV). The continuous tunable work function of Cu2−xS electrodes enables the ideal junction interface with ohmic contact properties of both n‐type and p‐type transition metal dichalcogenides materials. Our efficient work function engineering strategy provides an innovative way to design 2D electronics for the development of integrated electronics devices.