Flashback: May, 1977. Bianca Jagger, estranged Rolling Stones wife, Interview cover star and party girl par excellence takes to the floor of Studio 54 like a disco Lady Godiva atop a white steed. But unlike Godiva, Jagger is far from naked; instead she is draped in silk jersey, trussed with gold cord and glowing in the barrage of paparazzi flashbulbs. It's a heady cocktail of glamour, sex and celebrity that remains powerful and seductive – even today.

At least, that's what the head honchos of New York label-cum-legend Halston (the name inside that white jersey creation) hope. They include Harvey Weinstein, one of several investors who bought the label in 2007 and Tamara Mellon, who is on the board, and the new weapon to harness that enduring brand appeal: Marios Schwab. One of London's leading young guns – though when the phrase is mentioned he exasperatedly points out his age (32) while I tot up his catwalk outings (nigh on 10 seasons) – Schwab's cerebral, considered approach to fashion has seen him consistently dubbed the Next Big Thing.

That tag has come good now as Marios Schwab holds the somewhat grander title of creative director at Halston. Announced in May, the high-profile appointment has the fashion world buzzing. At first glance, Marios Schwab and the Halston founder could not be more dissimilar. Born Roy Frowick in Iowa in 1932, Halston dropped both first and last names upon his arrival in New York to be known only by his middle name – or, more enigmatically, "H", a self-made myth who in the words of the photographer Francesco Scavullo "invented pretentiousness" for Seventies America.

Schwab is anything but pretentious: a pragmatic Greek-Austrian alumnus of Central Saint Martins whose label, based in London's still-gritty far-East End, is literally and figuratively a thousand miles away from H's glamorous American excess. But how does Marios Schwab relate to Halston? How to reconcile this young designer known for sexy-but-severe intellectual attire with the tarnished Manhattan megalith best remembered for dressing the disco-crazed hordes of Studio 54? It seems their work, too, is worlds apart – yet despite being approached by sexed-up Italian conglomerates and dusty Parisian couture houses alike, Schwab declares that Halston was the only one that felt right. "When they approached me, I instantly thought 'This is the house I want to work for.' Sometimes, you just feel super confident about something."

It is interesting that he feels so "super confident", as for some frock-watchers Schwab's appointment comes from left-field. After all, he is lauded as a conceptual whizz-kid who has taken inspiration from medieval dissection manuals, hobbled models in floor-length tube-skirts and cracked cocktail dresses open like volcanic fissures. All a far cry from Liza and Bianca et al in jersey jumpsuits and Ultrasuede shirt-dresses, and rightly so: Schwab's appointment brings high concept to Halston.

In his own mind, Marios Schwab already has the Halston hallmarks down pat. "I like the era, the people, the fantasy. Halston was ultra-sophisticated, but with a punch. It wasn't boring, it was super sharp." All adjectives which could easily be ascribed to Schwab's own creations, albeit in a very different fashion. From the start, Schwab was sharper than most: his first catwalk outing under the auspices of new talent showcase Fashion East in 2005 made the press sit up and take note. Far from the show-off shenanigans of most early collections, Schwab's show was firm, focused and eminently wearable. Feted by taste-breaking American Vogue as "London's leading exponent of the early-Nineties revival", Schwab's spring/summer 2006 collection caught on to the Alaïa-like aesthetic that was then barely a blip on fashion's radar. "You want to wear something and look like a supermodel – or maybe a superwoman," Schwab states of that first show, while "supermodel" and "superwoman" are phrases that pop up throughout his conversation alongside much impassioned Mediterranean hand-gesturing. It's easy to imagine Schwab's burning passion for clothes, women and fashion in general inflaming even the coolest of Manhattan boardrooms.

The buzz around his potential succession to Halston's former head designer Marco Zanini, who left after just two seasons, began at Schwab's spring/summer 2009 show last September. It was a collection of twisty-turny jersey frocks, Grecian drapes and a sinuous slashed onesie snaked with golden rope. "These garments are about the body. This is my identity. I always wanted to create garments that are related to the body, because that's what we're actually covering." In retrospect, both the clothes and the thought behind them made it the perfect dress rehearsal for Halston – but the connection between the two designers is more subtle than that. Schwab himself states "Halston is sculptural in a fluid way, Marios Schwab in a less fluid way", and it's easy to relate Halston's method of wrapping abstract fabric shapes around the body to Schwab's own fiendishly complex garments that ripple around female curves like geodesic domes. If Andy Warhol praised Halston garments for their simplicity ("How American garments should be"), Schwab's creations may be complicated to construct, but are nevertheless deceptively simple to wear. As with Halston, that approach has won critical and commercial success: a roster of stars, including Chloe Sevigny, Sienna Miller and the singularly monikered Kate and Kylie have Schwab hanging in their wardrobes, while the label has 50-plus stockists worldwide.

For those who may consider this as Schwab selling out, his attitude to the age-old art versus commerce debate is refreshing. "I'm not going to create the 'It' bag. I don't think that's necessary, there are so many 'It' bags around. Do you think Dior created because he said to himself, 'I want to sell'? What's the point of being a creator if you don't start with the fantasy of fashion?" In a sense, this is what the Halston team have recruited Schwab to provide: an injection of his rigorous, intellectual vision into the brand and New York Fashion Week. At the same time, the launch of a new label, Halston Heritage – redeveloping iconic pieces from the label's archive at an accessible price point – will help offer the necessary financial support to give Schwab's fantasy a free hand when his first collection hits the New York catwalk in February 2010.

This month Schwab travels to New York, to meet his transatlantic creative team for the first time and finally get his hands on those archives. Whether Schwab will lean on those or go his own way is still to be decided: "I really love the brand, I love the history of Halston," he declares. "But I like doing things that are not obvious. I like a challenge." Challenging is certainly the word that comes to mind: Zanini left under something of a dark cloud after barely two seasons and subsequent lacklustre collections were created by a nameless design collective. Schwab's own reasons for accepting the job are as clean-cut as a Halston frock: "It just fits. It fits like a glove." If his creations follow the same simple formula, Halston is on to a winner.