Updated project metadata. The host cell cycle is a major target for manipulation by viral pathogens, which often replicate in certain cell cycle stages. The prevalent pathogen human cytomegalovirus (HCMV), for instance, only replicates during G1 and therefore employs diverse mechanisms for regulating cell cycle progression. Here, we demonstrate that the human enzyme sirtuin 2 (SIRT2) is required for HCMV-mediated cell cycle dysregulation. By combining virology assays with mass pectrometry-based proteome, acetylome, and interactome analyses, we have defined a pro-virus function for SIRT2 in regulating the G1 to S phase transition.