Localized surface plasmon resonance (LSPR) allows nanoparticles (NPs) to harvest light and concentrate it near the nanoparticle surface. Light energy is utilized in the generation of excited charge carriers as well as heat. Plasmonic catalysts used these energetic charge carriers (and the heat) to drive chemical reactions on their surface and allowed the discovery of novel and selective reaction pathways that were not possible in thermal catalysis. This review discusses the fundamentals of plasmonic catalysis and its application for CO2 conversion to fuel and chemicals. We first discussed the fundamentals of LSPR and the mechanism of plasmonic photocatalysis, using the concepts of the dielectric function, charge carrier generation, and relaxation pathways. We then reviewed various charge carrier-mediated activation of molecules (their chemical bonds) on the surface of plasmonic nanocatalysts and how the extraction of charge carriers played a critical role in plasmonic catalysis. The concept of multicomponent plasmonic catalysis, a hybrid catalyst by combining plasmonic metals (Cu, Au, Ag, Al, etc.) with nonplasmonic but active catalytic metals (Pt, Pd, Ru, Rh, etc.), in close proximity to each other, was then discussed. Photocatalytic CO2 reduction reactions using the examples of each of three major pathways, (i) direct transfer of hot charge carriers to the reactant molecules, (ii) providing heat to the reactant molecules by photothermal effect, and (iii) enhancing the photon absorption rate of reactant molecules by optical near-field enhancement close to the nanocatalyst surface, were discussed.