In Surrey and West Sussex the butterfly is sometimes double brooded, the first brood emerging as early as late April, or more typically in May; and the second brood ( which may be partial, or absent entirely ) emerging in late July or early August. In south Devon the butterfly is always double-brooded. In the remainder of Britain it is always single-brooded, emerging in late May, and remaining on the wing until late June or early July.

The egg, like that of other Pierids, is skittle-shaped, ribbed, and shiny. It is whitish in colour, and laid singly on the underside of leaves of various vetches and trefoils. The plants chosen are usually at the forest edge, and are typically shaded for between 25-50% of the day. Consequently most eggs are laid along narrow east-west rides, or along wide north-south forest tracks, often in situations where flowery embankments rise behind drainage ditches.

The foodplants used vary from site to site, and from brood to brood. At one Surrey wood for example, the first brood oviposits almost exclusively on bird's foot trefoil Lotus corniculatus, while the second brood lays on greater bird's foot trefoil Lotus uliginosus. At another nearby wood the eggs are laid much more commonly on bitter vetch Lathyrus montanus; and at sites in Dorset and Northants, meadow vetchling L. pratensis or tufted vetch Viccia cracca seem to be favoured.

The caterpillars hatch after about 2 weeks but are heavily parasitised by tine Trichogramma wasps which devour the developing larva before it is able to hatch.

The fully grown caterpillar is thin, pale green, with a yellow line along each side, and a dark green line along the back. It rests by day along the midrib of the leaves, or on the stems of it's foodplants, and feeds mainly nocturnally, leaving characteristic nibble marks on the edges of the leaves.

Wood Whites visit a wide range of nectar sources including greater stitchwort, bird's foot trefoil, wood forget-me-not, cut-leaved cranesbill, common spotted orchid, bugle and bitter vetch. Males can also sometimes be seen "mud-puddling" - imbibing mineralised moisture from damp ground; and are occasionally observed visiting herbivore dung.

On sunny mornings males patrol back and forth along woodland rides and around the edges of clearings in search of newly emerged females.

A ritual is often observed in which male and female sit face to face on a leaf, with wings closed. The male extends his proboscis and uses it to alternately "whip" each hindwing of the female. This action is repeated many times over the course of several minutes, during which time the female cowers with her antennae bent back. The male's antennae always project forwards and often dip to make contact with the female, presumably picking up chemical messages about her fecundity.

During this process the male periodically flicks his wings open and closed. The female responds with a similar signal. The butterflies become so engrossed in this activity that even if they are deliberately disturbed they simply fly a short distance to settle on another leaf, and resume the process, which can continue for as long as half an hour.

According to some authors the ritual is a precursor to mating, Wiklund and Thomas for example both state that a virgin female will respond by immediately curving her abdomen forward toward the male to demonstrate her willingness to mate. However I have observed the "courtship" hundreds of times over a period of several years, and have never seen it lead to copulation. I have however on several occasions found copulated pairs hanging below the leaves of bramble suckers, vetches and other low foliage. In Surrey, early one morning in May 2004, I found a mated pair of which the female was newly emerged and still drying her wings. The implication is that the true courtship ritual is probably a brief affair, and that the ritual described above comprises an elaborate rejection signal informing the male that the female has already mated. It seems odd though that a female would spend such a long time informing a male of her status, when she would make better use of her time egg-laying.

Overnight, and in dull weather, the butterflies roost in sheltered spots, often in little groups of 2 or 3, typically on the white flowers of stitchwort, on dandelion "clocks", or on the flowers of pendulous sedge or cock's foot grass heads.