"[3] In 2008, Chicago Tribuneart critic Alan G. Artner wrote "Postiglione has created a strong, consistent body of work that developed in cycles, now edging closer to representation, now moving further away, but remaining rigorous in approach to form as well as seductive in markmaking and color.

"[18] Influenced by artists such as Frank Stella, Brice Marden, and Robert Mangold, these works explored the nature of paintings as objects, and often coupled severe geometric abstraction with a sensual celebration of gesture and materials.

[13][20][21] For a time, Postiglione—described by critic Alice Thorson as "a prime mover in the geometric abstractionists' battle for recognition" in Chicago—and like-minded artists struggled to find a home beyond a handful of galleries supportive of their work, such as Jan Cicero and Roy Boyd.

His Scape and Passage works (1979–1986) drew comparisons to the paintings of Robert Moskowitz, reducing Chicago cityscapes and iconic structures like the Sears Tower to archetypal forms and shapes that paid "homage to the city's built environment (Daniel Burnham's grid plan, Frank Lloyd Wright's horizontal planes, Mies van der Rohe's vertical modules) and to the utopic vision its soaring edifices once embodied.

[30] These works often "rely on elegant line and subtle coloration as bait to seduce the eye and draw the viewer close"[31] in order to contemplate the entanglement of pandemic, mortality and interconnection in an increasingly globalized world as well as the "movement, precision and seduction"[32] of the dance.

Postiglione has moved beyond canvas and paper in his five Population exhibitions (2004–2016),[33] producing site-specific paintings and interactive and collaborative installations that address demographic growth and the attendant issues of interdependence, scarcity and conflict.

His written work includes features on Daniel Buren, Ed Paschke, Martin Puryear and Alexander Calder,[37] and exhibit reviews of Julia Fish, Michiko Itatani, Susan Michod, Dan Peterman, and Frank Stella, among many.

He has also written catalogue essays for numerous artists, including Tim Anderson, Alexandra Domowska, James Juszczyk,[38] Terrence Karpowicz, Arthur Lerner,[39] and John Phillips.

"[45] Many of these students would go on to enjoy long art world careers, including artists Barbara Blades, Carol Diehl, Bonnie Hartenstein, Ellen Kamerling, Elizabeth Langer, Fern Shaffer and Annette Turow, and gallery owner Jan Cicero.