Legionella pneumophila, a waterborne opportunistic pathogen, is known for causing Legionnaires’ disease, a community-acquired pneumonia. Central to its pathogenicity is the establishment of a replicative niche within human alveolar macrophages, facilitated by its type IVB secretion system (T4SS). While Legionella utilizes T4SS to translocate over 300 effector proteins into host cells to manipulate various cellular functions, only a handful are known to target mitochondrial functions. Through a combination of bioinformatic screening and immunofluorescence microscopy, we identified several novel Legionella T4SS effectors localising to mitochondria. Subsequent validation via mitochondrial sub‑fractionation and carbonate extraction confirmed the integration of these effectors into the mitochondrial outer membrane. Further investigation into one of these effectors via co‑immunoprecipitation and mass spectrometry revealed three catalytic subunits of protein phosphatase 1 (PP1) as its primary interacting partner, thus it is named LpPIP (L. pneumophila PP1-interacting protein). PP1, crucial in cellular phosphorylation events, functions alongside PP1‑interacting proteins (PIPs) as a holoenzyme. Notably, LpPIP contains the RVxF motif commonly found in mammalian PIPs, suggesting its potential role as a PIP mimic. Site-directed mutagenesis and immunofluorescence microscopy confirmed LpPIP’s ability to recruit PP1 to mitochondria using its RVxF motif. Phosphoproteomic analysis revealed a significant reduction in mitochondrial phosphopeptides in cells expressing FLAG-LpPIP, indicative of PP1‑mediated dephosphorylation of mitochondrial proteins. These findings propose that LpPIP, by mimicking mammalian PIPs, recruits the host's PP1 to the mitochondrial surface, thereby influencing mitochondrial functions. This study highlights the intricate strategies L. pneumophila employs to modulate host cellular processes during infection.