The 47-year-old creator, who quit Chloé in March, had never before tackled an haute couture collection – the handmade pinnacle of the fashion pyramid.
But she made both a daring and crowd-pleasing first bow late Tuesday, with a run of highly romantic dresses, mostly in black and white, on a set which evoked a moonlit garden.
The New York Times’ Vanessa Friedman called the show “dreamy”.
“It was really good… a study in sophistication,” she tweeted, proclaiming one shimmering layered silvery creation as “definitely an Oscars dress”.
The designer’s big innovation, however, was bringing men to the haute couture catwalk for the first time at Givenchy.
Of the big labels, only Dolce & Gabbana has ever previously presented men’s haute couture.
The rocky romanticism of Waight Keller’s male creations was a clear grab for a high-end market that is dominated by the bespoke tailors of Milan and London’s Saville Row.
Waight Keller, who made her name by turning Pringle of Scotland from a rather staid knitwear maker into a fashion brand, had a lot to live up to.
Outgoing Italian creator Riccardo Tisci had transformed the brand long associated with Audrey Hepburn and Jackie Kennedy both financially and stylistically in his 12 years at the helm.
His edgy, Gothic-inspired look brought a long line of stars to the label like Beyoncé, Madonna, Kanye West, and his wife Kim Kardashian.
Although he let the haute couture end drop in recent years, his T-shirts and a series of “It” bags were big sellers.
Reactions to the Giorgio Armani Prive show, which brought French stars Marion Cotillard and Isabelle Huppert, as well as German actress Diane Kruger, to the front row, were decidedly more mixed, however.
The veteran designer’s “evening shorts” and crystal leggings got short shrift from some critics, as did another creation which Friedman described as “paillette-covered bloomers”.
The haute couture shows, which are unique to the French capital, are the peak of the fashion industry, with thousands of hours sometimes going into the handmade dresses that can be afforded only by the richest people on the planet.