•Delivery service contributed to the sales of restaurants during the COVID-19 pandemic.•Casual and fast casual dining restaurants had more benefit from delivery service than fine dining ones after COVID-19 restrictions were eased.•Discount options failed to increase sales during the pandemic.•Brand effects on restaurant financial performance were stronger after the COVID-19 outbreak. To contain the pandemic of coronavirus (COVID-19), social distancing, self-isolation and travel restrictions have been imposed globally. To shed light on how COVID-19 is affecting restaurant industry, this study aims to explore the factors that affect restaurant firms’ financial turnaround for their sustainability after the business shutdowns amid the COVID-19 pandemic. By utilizing a total of 86,507 small- and medium-sized restaurant firms’ sales data collected from nine cities in Mainland China, the exploratory approach of this study successfully determines positive impacts of three aspects of operational characteristics (i.e., delivery, discounts, and service type) and brand effects as uncertainty minimizing factors amid distinctive business shutdowns and restrictions. This is the first empirical study in the management realm on the impacts of COVID-19 on restaurant industry. This paper strengthens the extant literature by highlighting the impact of COVID-19 on the restaurant industry after the business restrictions are lifted.