Of every label that showed at Mercedes-Benz Fashion Week last year, it was Macgraw’s squad of smiling models that instantly captured hearts.

With a backdrop resembling a pink dollhouse, and a '60s pop soundtrack, the positivity on the catwalk was infectious. Vogue called it “a celebration of the joy in dressing up” and Grazia named it “the most fun fashion week show … by far.”

In 2015, designers Tessa and Beth MacGraw had hoped for the same reaction. The show was certainly fun, but the sisters had asked their 2015 runway models to smile and so rare is the request in designer fashion, all they got were a lot of closed-mouth grins. Barely a tooth was seen.

“So we started casting smiles the next year,” says Beth. “If a girl came in and couldn’t smile, she didn’t get the show.”

That hallmark remains. At the label’s show earlier this week in Sydney, models with crowns of braids smiled sweetly as they walked, and for the finale, they danced. Glittering red hearts decorated tiered skirts and crowned swans adorned sky-blue ruffle shirts and black tailored suits.

That playfulness and joy is a Macgraw trademark, and a direct reflection of the way Tessa and Beth interact. Our phone interview is littered with laughter. Keeping track of who’s saying what becomes tricky when they swoop in to finish each other’s sentences. By their own admission, they’re so happy in each other’s company that it’s “gross”.

“I know we can spend every single day with each other,” says Beth. Working with family “you know your business partner’s not going anywhere. You trust them implicitly. Just having a friend there to cry, laugh, high-five and pack orders with until five in the morning ... it’s an absolute bonus.”

Since winning the 2016 National Designer Award (and in the same year, the BT Emerging Fashion Designer Award, The Regional International Woolmark Prize and The Australian Fashion Laureate for Best Emerging Designer), Macgraw’s ascent has been swift. Most recently the brand was picked up by Hong Kong’s prestigious Lane Crawford boutique, adding to a stockist list that includes luxury online fashion platforms including Farfetch and Moda Operandi. The UK and US are the brand’s biggest markets.

“We probably learned more from the National Designer Award the year we lost, in 2015,” says Tessa. “We thought we were doing pretty okay, but that year made us focus more on all the parts in our business.”

Sharpening their business skills meant taking greater care in balancing the number of runway-ready pieces with highly sellable garments. While Macgraw’s ruffled organza gown commands the attention of cameras, it’s the label’s button down blouses that boosts sales.

It also meant renegotiating trading terms. “We made sure we got deposits out of everybody, then made sure that they paid the remaining balance within 30 days,” says Tessa. “It’s kind of obvious, but not everyone is doing it.”

Running a fashion label together was a childhood dream realised only in 2012, when Tessa and Beth “finally got their act together”. Beth had previously been working in fashion PR, while Tessa had studied fashion and was working as a fashion buyer.

Their 2014 collection helped recruit new fans and earned them editorial recognition, and by 2015 Vogue editor-in-chief Edwina McCann and fashion director Christine Centenera lined Macgraw’s front row at fashion week. This year’s front row included singer Sarah Blasko and bloggers Nadia Fairfax, Carmen Hamilton and Sara Donaldson.

The sisters spent their childhood dancing and designing dresses for Barbies –influences you can spot in Macgraw’s Mattel-pink or vermillon runways and theatrical, ruffled dresses. Against the backdrop of fashion’s current obsessions (street wear, fetish-wear and various other subcultures), Macgraw’s unbridled femininity, and light-hearted approach to dressing feels fresh.

“It’s fun for us to push ruffles,” says Tessa. “It’s a nod to the Renaissance and Edwardian periods too,” Beth adds. “We love opulent fabrics, but we love our silhouettes to be clean and easy to wear. We like to style frills with a tougher boot too. Our girl is still a cool girl.”

With awards under their belt and a steadily rising international profile, the pinch-yourself moments are rolling in fast. Last year, Julianne Moore was photographed wearing Macgraw’s Bell top in a UK Marie Claire editorial. The look went on to become the highest selling product for the brand in the UK.

Then of course, there was Paris in January, where Tess and Beth presented Macgraw to a judging panel including Net-a-Porter founder Dame Natalie Massenet and Victoria Beckham, as part of the International Woolmark Prize. “It was an out-of-body experience,” says Tess. “Looking out and having them hang off your every word was the most ridiculous moment of our lives.”

Next is showing a resort collection at New York Fashion Week in September.

In the meantime, the MacGraws will be back assembling furniture in their new office. “We’re in full Ikea mode,” Beth says as our conversation draws to an end. “It’s not all fashion shows and macarons, for sure.”