The C–N coupling of alkyl electrophiles for amine synthesis is a less-developed area in comparison with that of aryl electrophiles largely because of the difficulty in product-generating C(sp3)–N reductive elimination. The recent work by Hu et al. (Nat. Catal. 2018, 1, 120–126) developed an effective strategy for the C–N coupling of alkyl redox-active esters with anilines by merging photoredox catalysis and copper catalysis with an oxoacetic acid ligand (LH2). Here, we present a DFT-based computational study to understand how the special dual catalysis works in a cooperative fashion with the assistance of the ligand. Photoredox catalysis is found to occur most possibly through an oxidative quenching mechanism (RuII/*RuII/RuIII/RuII) with Et3N as the quencher rather than with the experimentally proposed copper complex. Copper catalytic cycle (CuI/CuII/CuIII/CuI) is predicted to proceed via a CuI-oxidation-first pathway instead of the hypothetical aniline-deprotonation-first pathway in the experiment, and the most likely catalytic active species is identified as the CuILH complex. With the RuII/CuI-metallaphotoredox catalysis, the most feasible mechanism for the C(sp3)–N cross-coupling involves six steps: (i) generation of cyclohexyl radical (Cy•) via the single electron transfer (SET) from photoexcited *RuII to the complex of redox-active ester with CuI, (ii) coordination of aniline to CuI center, (iii) Cy• radical addition to CuI center, (iv) SET between CuII-cyclohexyl aniline complex and generated Et3N•+, (v) deprotonation of aniline, and (vi) reductive elimination of the CuIII-cyclohexyl amido intermediate to produce the C(sp3)–N coupling product. The CuI complex is identified to play a dual role in the title reaction, which acts as the promoter in oxidative quenching process and as the catalyst in the copper catalytic cycle.