It breeds on 24 offshore islands between Namibia and Port Elizabeth. Additional colonies were established in the 1980s on the mainland at Betty's Bay and Simonstown. There is also a colony on the mainland of Namibia, although it is not known when this colony was established. Nesting on the mainland is unusual for jackass penguins because they are ground-nesting birds and are vulnerable to the many predators on the mainland. Most of the nutrient-rich guano was removed for fertiliser in the 19th century.
Penguins now nest in burrows in sand, under overhanging rocks, under bushes, or even in the open.
Jackass penguins can breed at any time of the year, usually laying two eggs. Most adult birds feed during the day and the chicks are fed regurgitated food in the late afternoon. The parent birds take turns in guarding the nest site and catching food. Fish eaten include sardine, maasbanker and anchovy. Squid are also eaten.