This study investigates whether a complementary co-investment relationship exists between business angels and venture capitalists (VCs) in U.S. start-ups, and if so, whether the centrality of angel investors amplifies this effect. Drawing on panel data from PitchBook and LinkedIn, the analysis examines quarterly observations of various start-up financing rounds. Regressions with high-dimensional fixed effects are employed, where the dependent variable is a binary indicator for obtaining new VC investment, and key independent variables include an indicator for prior angel funding as well as four centrality measures characterizing the angels’ network positions.The results show that prior angel funding not only is associated with the increase of a start-up’s likelihood of securing new VC investment but that this effect is amplified when the involved business angel occupies a more central position in the network, especially when those connections are with other well-connected angel and VC investors, and when the investors occupy central positions within the overall network. These findings remain robust when restricting the angel funding to angel investments in the first financing round of startups and when applying propensity score matching (PSM) to identify start-ups that are likely to receive angel funding but haven’t receive angel funding to reduce potential selection bias. This study highlights the crucial role that well-connected angel investors play in enhancing access to venture capital, providing valuable insights for entrepreneurs, investors, and policymakers aimed at strengthening startup financing mechanisms.