A polymer-lipid hybrid nanocarrier was developed to encapsulate psoralen (PSO) to improve its water solubility and bioavailability. The effects of PSO-loaded polymer-lipid hybrid nanoparticles (PSO-PLNs) on breast cancer MCF-7 cells were investigated. PSO-PLNs were prepared through a nanoprecipitation method and were optimized by a central composite design-response surface methodology using particle size and entrapment efficiency as indices. Dynamic light scattering and transmission electron microscopy analysis confirmed the physicochemical characterizations of PSO-PLNs, which had an average size of 93.44 ± 2.39 nm and a zeta potential of −27.63 ± 0.31 mV. In vitro drug release of PSO-PLNs was evaluated using dialysis and showed a delayed release compared with free PSO. The in vivo anticancer efficiency of PSO-PLNs was appreciated using a MCF-7 breast tumor model. Administration of PSO-PLNs showed similar antitumor efficacy but lower toxicity compared with doxorubicin. Our designed nanocarriers successfully optimized the pharmacokinetics of PSO via improved systemic delivery.