‘This is the first night. You might as well try stuff,’ pianist and composer Jason Moran told the rapt audience of his solo recital to inaugurate the restored Veterans Room of New York’s Park Avenue Armory.

His playfully and mesmerisingly experimental approach echoed that of the room’s original designers – Louis Comfort Tiffany, Stanford White, and Candace Wheeler, then at the beginning of their careers and poised to create a multi-layered masterpiece of the American Aesthetic Movement – as well as the one embraced by Herzog & de Meuron in revitalising the historic space.

A civic commission awarded in 1879 to Louis C Tiffany and Co, Associated Artists, the Veterans Room has been restored as part of the ongoing $210-million transformation of the Armory: a cavernous, quirky palace that excels at cultural programming ranging from the boldly exquisite to the exquisitely bold.

Herzog & de Meuron are proceeding room by room (4 down, 14 to go), working with Platt Byard Dovell White Architects to highlight the unique character of each interior while integrating contemporary, functional upgrades. It is a project of subtlety in the service of exuberance, and both are finely calibrated.

‘It’s adaptive reuse on steroids,’ says Rebecca Robertson, president and executive producer of the Armory. ‘You’re taking important rooms that will be counterbalanced by more contemporary interventions when there’s less historic fabric left, and then of course they have a new use, which is contemporary performances and art.’

Dense with decoration and techniques, the Veterans Room unfolds as a kind of ornamental sampler. Unifying the disparate motifs – mythological creatures, Celtic knots, Moorish medallions, a frieze of illustrated war stories – is an immersive effect of architectural embroidery that for all its honeyed oak pays homage to metal: sure and solid, with a dark gleam.

Even the jewel tones are fugitive: Tiffany windows appear to be accented by blue in one light and red in another (a favourite feature of Jacques Herzog, they are newly backed by glass), a mosaic over the freshly rebuilt fireplace flickers between lapis, turquoise, and malachite.

For Herzog & de Meuron senior partner Ascan Mergenthaler, it is the room’s ‘level of inventiveness and playfulness’ that sets it apart from others at the Armory. ‘It is a collage of diverse influences and inspirations, reflecting the collaborative efforts of an outstanding team of designers,’ he adds.

The restoration unveils and celebrates what was a deliberately unconventional space through additions ranging from overhauled lighting and advanced acoustics to wallpaper (an interlinked pattern with a shape-shifting quality) and curtains of leather and metal mesh that replace Wheeler’s lost textiles.

The piano recital was the dynamic kickoff to a series of ‘Artist Studio’ performances organised by Moran. After filling the room with original compositions involving finger-blistering glissandi and a darkly primal bubbling of tones, he called for the lights to be dimmed.

‘I just want to play something in this light,’ said Moran, before beginning his final piece beneath LED-illuminated lenses that offer a 21st-century approximation of a gaslit glow. ‘It’s new light.’