The peacock can be found in woods, fields, meadows, pastures, parks, and gardens, from lowlands up to 2,500 metres (8,200 ft) elevation. It is a relatively common butterfly, seen in many European parks and gardens. The peacock male exhibits territorial behaviour, in many cases territories being selected en route of the females to oviposition sites.
The butterfly hibernates over winter before laying its eggs in early spring, in batches of up to 400 at a time. The eggs are ribbed, olive green, and laid on the upper parts and the undersides of leaves of nettle plants and hops. The caterpillars, which are shiny black with six rows of barbed spikes and a series of white dots on each segment, and which have a shiny black head, hatch after about a week. The chrysalis may be either grey, brown, or green in colour and may have a blackish tinge. The caterpillars grow up to 42 mm in length.
The recorded food plants of the European peacock are stinging nettle (Urtica dioica), hop (Humulus lupulus), and the small nettle (Urtica urens).
The adult butterflies drink nectar from a wide variety of flowering plants, including buddleia, willows, dandelions, wild marjoram, danewort, hemp agrimony, and clover; they also utilize tree sap and rotten fruit.