Ultra‐high‐performance concrete (UHPC) is already gaining in‐field applications in bridge deck rehabilitation. On the other aspect, an innovative NC‐UHPC composite deck system was motivated to promote accelerated bridge construction (ABC) implementation of a newly built bridge, of which the precast UHPC substrate serves as the formwork for the cast‐in‐place NC overlay. Performance characterizations were investigated by loading five decks, of various UHPC thickness and w/wo longitudinal or transverse rebars. Their effects on the composite decks’ failure patterns and load‐deflection curves were quantitatively analyzed. Besides, digital image correlation (DIC) technique was adopted to adequately capture their damage evolutions. Moreover, analytical solutions for predicting a composite deck’s flexural and shear strengths are tentatively derived. Finally, 3D finite element (FE) models are developed within ATENA framework, capable of embracing the NC‐UHPC interface’s behaviors. Numerical predictions agree well with the experimental results and can benefit further researches evolving a NC‐UHPC composite deck system.