Mobile payments have emerged as a viable alternative to cash and credit cards and are rapidly gaining popularity worldwide. Limited research has explored the effects of mobile payments on restaurant performance from the perspective of restaurateurs. This study utilized a combination of the innovation diffusion theory (IDT) and the technology acceptance model (TAM) to investigate the influence of a near-field-communication (NFC) mobile payment environment on restaurant operating performance (ROP). Through convenience sampling, questionnaires were distributed to restaurant owners and managers, resulting in 279 valid responses. The empirical findings revealed that sales growth (β = 0.478), cost savings (β = −0.236), flexibility (β = 0.117), accessibility (β = 0.184), and trust and safety (β = 0.286) significantly impacted ROP. When considering restaurant size as a moderator for analysis, only two constructs, namely, accessibility (β = 0.108) and trust and safety (β = −0.160), showed significant impacts on ROP. These empirical insights offer valuable references to restaurateurs for enhancing ROP by leveraging the mobile payment environment.