Abstract The objective of this study was to investigate the association between a Parkinson’s disease (PD)-specific polygenic score (PGS) and protective lifestyle factors on age at onset (AAO) in PD. We included data from 4367 patients with idiopathic PD, 159 patients with GBA1 -PD, and 3090 healthy controls of European ancestry from AMP-PD, PPMI, and Fox Insight cohorts. The association between PGS and lifestyle factors on AAO was assessed with linear and Cox proportional hazards models. The PGS showed a negative association with AAO ( β = − 1.07, p = 6 × 10 –7 ) in patients with idiopathic PD. The use of one, two, or three of the protective lifestyle factors showed a reduction in the hazard ratio by 21% ( p = 0.0001), 44% ( p < 2 × 10 –16 ), and 55% ( p < 2 × 10 –16 ), compared to no use. An additive effect of aspirin ( β = 7.62, p = 9 × 10 –7 ) and PGS ( β = − 1.58, p = 0.0149) was found for AAO without an interaction ( p = 0.9993) in the linear regressions, and similar effects were seen for tobacco. In contrast, no association between aspirin intake and AAO was found in GBA1 -PD ( p > 0.05). In our cohort, coffee, tobacco, aspirin, and PGS are independent predictors of PD AAO. Additionally, lifestyle factors seem to have a greater influence on AAO than common genetic risk variants with aspirin presenting the largest effect.