Abstract: Recently, mixed-dimensional p-n heterojunctions have shown desirable optoelectronic functionalities. However, relatively little is known about the influence of interfacial traps on electron transport under external bias. Here, we explore the prominent dual optoelectronic characteristics of n-MoS2/p-GaN heterostructures, including photodetection and persistent photocurrent (PPC). The photoresponsivity was found to achieve as high as ∼105 A W−1 for 532 nm laser illumination under reverse bias. Additionally, the device exhibits the long-lasting PPC with a decay time constant (460 s) under forward bias. The results indicate that the hybrid heterojunctions not only function as high performance photodetectors under reverse bias but also have potential to use the unique property of PPC for other optoelectronic applications under forward bias alternatively.