R744 is an attractive refrigerant for medium- (MT) and low-temperature (LT) refrigeration but suffers from reduced capacity and energy efficiency at high ambient temperatures, which is of particular concern for applications such as transport refrigeration. This paper describes the design of a multi-temperature refrigerated container, with a subcritical scroll compressor used to provide the LT capacity. To improve unit performance at the high ambient conditions, recent advances in R744 technology have been implemented, including multi-stage transcritical compression with intercooling, improved gas cooler design to minimize approach temperature, and ejector expansion work recovery. Details of the system design and component selection are presented and discussed. The experimental results show that the for ambient temperatures between 25 and 50°C, the prototype R744 container achieves MT capacity in the range of 5.4 to 3.4 kW, LT capacity in the range of 4.1 to 2.3 kW, and unit COP in the range of 1.60 to 0.75.