Porphyromonas gingivalis is a keystone periodontal pathogen implicated in a variety of diseases ranging from periodontitis to Alzheimer’s disease. A hallmark of P. gingivalis is the constitutive production of a peptidyl-arginine deiminase (PPAD), which converts positively charged arginine residues into charge-neutral citrulline residues. The PPAD enzyme is known to be localized to the bacterial outer membrane and outer membrane vesicles (OMVs). Our present study was aimed at dissecting the roles of PPAD in the bacterial evasion of human macrophages and passage of cellular barriers. Here, we show that PPAD is required for activity of the arginine-specific proteases RgpA and RgpB, which are critical virulence factors of P. gingivalis. Furthermore, we show that the absence of PPAD leads to an increased OMV charge. Both changes impact the immune evasion strategy of P. gingivalis, as the PPAD-deficient bacteria display increased biofilm formation while their ability to evade and kill human macrophages is strongly reduced. In fact, PPAD-deficient bacteria and OMVs are more effectively internalized by macrophages and they elicit altered inflammatory macrophage responses, as demonstrated by reduced secretion of pro-inflammatory cytokines and major changes in the macrophage proteome. Intriguingly, we show that P. gingivalis OMVs have a high propensity for in vitro blood-brain barrier passage through transcytosis, which is significantly increased by PPAD-deficiency. This implies that OMV citrullination is a critical determinant for trafficking of P. gingivalis-derived vesicles within the human host. Altogether, our present findings explain how PPAD shapes the immunomodulatory and invasive properties of P. gingivalis and its OMVs.