This study examined the inhibitory effects of varying concentrations of licorice extract on the growth of Paraclostridium bifermentans spores and the quality changes in ready-to-eat (RTE) chicken breast under different storage temperatures. Results indicated significant inhibition (P < 0.05) of P. bifermentans spore growth at licorice extract concentrations ≥ 12.5 mg/mL, especially in 50 mg/mL. Compared with control group, the shelf life in treatment group (50 mg/mL licorice extract) was nearly prolonged 2-fold when storage at 15 and 20 °C. Furthermore, the Gompertz and Logistic models demonstrated a strong fit (R2 > 0.98) with the growth patterns of P. bifermentans spores at 15, 20, and 25 °C. The Ratkowsky model provided a more detailed elucidation of the relationships among temperature, maximum growth rate, and lag phase across varying concentrations of licorice extract. The model results demonstrated that licorice extract significantly (P < 0.05) inhibited the P. bifermentans spore growth in RTE chicken breast during storage. Additionally, compared to control group, the licorice extract-treated RTE chicken breast exhibited significantly lower levels (P < 0.05) of pH value, thiobarbituric acid reactive substances (TBARS) value, and total volatile basic nitrogen (TVB-N) content. Correlation analysis indicated a significant positive correlation (P < 0.01) between the quantity of P. bifermentans spores and the pH value, TBARS value, and TVB-N content when storage at 15, 20, and 25 °C. This study provides a theoretical reference for extending the shelf life and maintaining the quality of RTE chicken breast, offering valuable insights for improving meat safety and quality in industrial processing.