Males' abdomens are yellow-orange to orange-brown with blackish mottling, and on the upper sides are black and light orange hairs, and nine white tufts.

Those of females are pale yellow and have black markings with scattered white and orange-brown hairs on the upper side.

They usually mate on a web or on a dragline made by the female, and P. schultzi typically copulates for about 100 seconds, while others in the genus can take several minutes or even several hours.

Contests between Portia females are violent, and embraces in P. schultzi typically take 20 to 60 seconds.

The abdomens of females are pale yellow with black markings, and the upper sides have scattered white and orange-brown hairs.

Males' abdomens are yellow-orange to orange-brown with blackish mottling, and on the upper sides are black and light orange hairs and nine white tufts.

Those of females are pale yellow and have black markings with scattered white and orange-brown hairs on the upper side, but no tufts.

[4]: 88-89  All species of the genus Portia have elastic abdomens, so that those of both sexes can become almost spherical when well fed, and females' can stretch as much when producing eggs.

[6]: 495 When not hunting for prey or a mate, Portia species, including P. schultzi,[5]: 31  adopt a special posture, called the "cryptic rest posture", pulling their legs in close to the body and their palps back beside the chelicerae ("jaws"), which obscures the outlines of these appendages.

When walking, most Portia species have a slow, "choppy" gait that preserves their concealment: pausing often and at irregular intervals, waving their legs continuously and their palps jerkily up and down, moving each appendage out of time with the others,[7][8]: 6  and continuously varying the speed and timing.

[10]: 574  Unlike those of most jumping spiders, P. schultzi′s draglines stick to each other and, when a P. schultzi has laid a few lines across a gap, it uses these as walkways and reinforces them with additional silk as it moves.

Perhaps P. schultzi gains little from being alerted to objectives at distances because this spider moves so slowly that it is very unlikely to reach a more distant target in time to catch it.

[19][a] A Portia spider takes a relatively long time to see objects, possibly because getting a good image out of such tiny eyes is a complex process and needs a lot of scanning.

[13] Spiders, like other arthropods, have sensors, often modified setae (bristles), for smell, taste, touch and vibration protruding through their cuticle ("skin").

[13] When not joined to another spiders', a P. schultzi female's capture web may be suspended from rigid foundations such as boughs and rocks, or from pliant bases such as stems of shrubs.

[3]: 424  Where the web is sparse, a Portia will use "rotary probing", in which it moves a free leg around until it meets a thread.

[3]: 440-441, 444 The webs of spiders on which Portias prey sometimes contain dead insects and other arthropods which are uneaten or partly eaten.

In addition to P. schultzi, the table shows for comparison the hunting performances of P. africana, P. labiata and three regional variants of P.

Notes on this table: For resting, all Portias spin a horizontal web whose diameter is about twice the spider's body length and is suspended only 1 to 4 millimetres below a leaf.

A test suggested that P. schultzi′s hunting is stimulated only by vision, as prey close but hidden caused no response.

P. schultzi retreats from the sudden flights of houseflies found in the open, but sometimes takes flies entangled in a web.

[5]: 37 Unlike the Queensland variant of P. frimbriata, P. schultzi has no special tactics when hunting other jumping spiders.

[31] Before courtship, a male Portia spins a small web between boughs or twigs, and he hangs under that and ejaculates on to it.

[10]: 572-573  Females of many spider species, including P. schultzi, emit volatile pheromones into the air, and these generally attract males from a distance.

[25]: 343  A propulsive display is a series of sudden, quick movements including striking, charging, ramming and leaps.

If the male stands his ground and she does not run away or repeat the propulsive display, he approaches and, if she is mature, they copulate.

[c][5]: 33 For moulting, all Portias spin a horizontal web whose diameter is about twice the spider's body length and is suspended only 1 to 4 millimetres (0.039 to 0.157 in) below a leaf.

[5]: 30 P. schultzi, along with a large variety of spiders and insects, is often found in the dense, large webs of the diplurid Ischnothele karschi[c] (about 15 millimetres long[5]: 31 ), which are especially abundant in partly cleared secondary bush where rain forests have been cut down, and usually about one metre above the ground.

P. schultzi is also found in its own web and those of other spiders, on tree trunks and the walls of buildings, and in leaf litter.

[6]: 491  Molecular phylogeny, a technique that compares the DNA of organisms to reconstruct the tree of life, indicates that Portia is a member of the clade Spartaeinae, that Spartaeinae is basal (quite similar to the ancestors of all jumping spiders), that Portia′s closest relative is the genus Spartaeus, and that the next closest are Phaeacius and Holcolaetis.