On the track Mimoun won three Olympic silver medals, finishing second behind Emil Zátopek in the 10,000 metres final in 1948 and again second behind him in both the 5,000 metres and 10,000 metres finals in 1952. He was also the silver medallist in both events behind Zátopek at the 1950 European Athletics Championships. From 1949 to 1958, he won four individual gold medals and two individual silver medals at the International Cross Country Championships. He was a four-time gold medallist at the Mediterranean Games, completing the 5,000 m/10,000 m double in both 1951 and 1955.