Mutant oncogene DJ1 L166P has been linked to a familial form of early-onset Parkinson’s disease (PD). The DJ1 mutant deformed C-terminal helices and prevented the formation of a functional DJ1 dimer. Intriguingly, chaperon modulator, BCL2-associated athanogene (BAG1), has been shown to repair DJ1 mutant and restore its functions. Molecular simulation techniques were employed to elucidate protein–protein interactions between BAG1 and DJ1. Interaction of BAG1 with DJ1 showed recovery of disrupted alpha helix structures and H-bonds stabilizing the functional site Cys106. The His126-Pro184 H-bond (hydrogen-bond) critical to maintaining dimer interfaces was also restored and led to the restoration of dimer formation. High conformational to functional DJ1 dimer was confirmed root mean square deviation = 0.74 Å). Results of this suggest several molecular insights on BAG1–DJ1 repair mechanism and may have an impact on advancing PD treatments.