This paper aims to unearth the factors that influence scientists in becoming and choosing to become publicly funded principal investigators (PIs). PIs are the linchpins of knowledge transformation and bridging triple helix actors, particularly academia-industry. At a micro level, PIs are at the nexus of engaging and interacting with other triple helix actors. No study to date has specifically focused on the factors that influence scientists to become or choose to become publicly funded PIs. For scientists taking on the role of a PI represents an important landmark in their research career. Set in an Irish research system we found two main categories of influencing factors - push and pull. Pull factors are where the PI has more choice in choosing to become a PI, where as push factors is where the PI has less choice in choosing to become a PI. Pull factors we identified were control, career ambition and advancement, personal drive and ambition. Pull factors we identified were project dependencies and institutional pressures.