The town has traditionally lived of fishing. The nearby harbour of Nogersund is the third largest fishery harbour in Sweden. The fishery industry is also dominant on the peninsula. Listerlandet is also the fur farming centre of Sweden. Fur farming is currently under heavy political debate in Sweden.
Mjällby is known for its football team which has played in the Swedish national football league a few times. Among footballfans in Sweden the team of Mjällby AIF is known as "the team that always returns". In September 2009 the team once again qualified for the highest division and plays since the 2010 season in Allsvenskan.