The journey of the theoreticalTheoretical study of semiconductorsSemiconductor is reviewed in a non-conventional way. We have started with the basic introduction of Hartree–Fock method and introduced the fundamentals of the Density Functional Theory (DFT)Density Functional Theory (DFT). From the oldest Local Density ApproximationsLocal Density Approximation (LDA) (LDA) to the most recent developments of semi-local corrections [Generalized Gradient Approximation (GGA)Generalized Gradient Approximation (GGA), Meta-GGAs], hybrid functionalsHybrid functional, and orbitalOrbital-dependent methodologies are discussed in detail. To showcase the performancePerformance of DFTDensity Functional Theory (DFT), results obtained via different approximationsApproximation are compared. We indicate the success of semi-local approximationsApproximation in predicting structural propertiesStructural properties of materials. We also show how a computationally less expensive but robust architecture of some semi-local DFTDensity Functional Theory (DFT) methods can solve the long-standing puzzle of band gap underestimationBand gap underestimation. In semiconductorSemiconductor physics, it’s crucial not just to predict the band structureBand structure accurately but also to calculate the Fermi energyFermi energy precisely and determine the exact band alignmentBand alignment. The comparison of Fermi energyFermi energy-dependent properties can channelize the theoreticalTheoretical studies on modern age environmentally friendly researches on semiconductorsSemiconductor, such as artificial photocatalysisPhotocatalysis, energyEnergy-efficient optoelectronic devicesOptoelectronic device, etc. This prescription on proper choice of DFTDensity Functional Theory (DFT) method is potentially competent to complement the experimentalExperimental findings as well as can open up a pathway of advanced semiconducting materials discoveries.