Zac Posen tucked himself into one of two linen chairs in his unfinished new office on 54th Street and Fifth Avenue. The walls, including those in the showroom that served as a runway, were still Sheetrocked. Team Posen moves in next month, and they couldn’t control their excitement about the new address: They clearly take their cues from their leader.

Posen is one of the most cheerful, hardworking fellows in New York. In the last few days, he has already shown his ZAC Zac Posen collection and filmed Project Runway. And from the way he mentioned “dialogues with retailers” in regard to his main collection, it’s clear his Spring brief is to find that sweet spot between art and commerce. And he’s up for the challenge. “At the end of the day, we’re here to sell clothes,” he said.

About those clothes. Posen wanted to find a balance between classicism and sexiness. He mentioned there would be more separates, a general toning down of volume and amping up of ease. He delivered on that promise with the starting white pantsuit in neoprene-bonded crepe with a molded peplum detail, and the subsequent snug black and white eyelet day dresses that nipped at the waist. White, black, and red were his only colors, and each was shown tonally. That way, “you can concentrate on the tech construction and cut of the clothes,” said Posen. Indeed, up close, his tailoring was terrific, as was his enthusiasm for subtle touches of drama like a high-waisted bustle cocktail dress or gowns with Brancusi-like curves and stiff contours. While some of the gowns were too restrictive and hard to walk in, all of Posen’s ideas seemed to come together in the final look, an ivory guipure gown with starburst embroidery. It was optimistic, sweet, and had a touch of bridal glamour (down to the Truly Zac Posen diamond engagement ring the model was wearing).