“Oh, this is tougher than I thought,” says Jackie Lee, her cheeks blushing crimson as she stares into our camera at her Hackney studio. “I get shy around lots of people – it takes time getting used to.”

Quietly but surely, the Seoul-born designer has been opening London Fashion Week for several seasons now, following her first presentation in 2011. Her minimalist womenswear collections have never grabbed the headlines quite like those of her Central Saint Martins cohort (class of 2010) such as Simone Rocha and Thomas Tait. But then, that was never Lee’s aim. “The J. JS Lee woman is quiet but strong. She doesn’t make a lot of noise but she has self confidence,” says the designer.

Shouters, they are not. But Lee’s beautifully constructed, unfettered clothes boast a quiet confidence and versatility that make perfect sense for modern women who don’t rely on frills to make a statement. Her autumn/winter 2016 collection took this idea further, with her separates and dresses riffing on menswear silhouettes and bold, 80s suiting, but reworked with a lighter, modern touch. “This was a collection about empowerment. I wanted to make the J. JS Lee woman powerful,” she says. Holding out a grey blazer from the autumn/winter 2016 collection, she explains, “I asked a menswear pattern cutter to create a womenswear form using sleeves from traditional menswear.”

Female empowerment was also the idea that tied together the five pieces she designed for the Fashion and Freedom exhibition, opening at Manchester Art Gallery this Friday. Alongside five other female designers, including Vivienne Westwood and Roksanda Ilincic, Lee has created looks influenced by the changing roles of women and fashion during World War I. "One of the pieces for the exhibition is a trench coat made with French tweed that is similar to one of the multicoloured versions from my autumn collection," says the designer. "Of course, trench coats were popularised during World War I. I put my own twist on it though with fringe details and volume."

Though Lee always aspired to work in fashion, her start in the industry was defined by compromises. “It was a difficult time for Korea,” she recalls of the early noughties when the Asian financial crisis of the late 90s was still taking its toll. “After I graduated [from Chungnam National University], instead of having a job as a designer, I turned to pattern cutting, which was more practical.”

Four years into her job as a pattern cutter at several local labels, Lee decided to quit. “Suddenly, I woke up and thought, ‘my dream isn’t to be a pattern cutter.’ I wanted to be a designer but I’d just forgotten it,” she says. Shortly thereafter, she applied for the MA fashion design course at Central Saint Martins. She was accepted – but only after a gruelling face-to-face interview with the late Louise Wilson, the course’s formidable director.

“I was thinking to myself, what kind of woman shouts at a person she’s never met before?” she laughs. “But during the course, she helped me so much.”

The effort paid off. In 2010, almost all of her graduate collection was bought by Harrods, from whom Lee also received the Harrods Design Award. The same year, she launched her eponymous label. Since then, her clothes have found their way into women's wardrobes and earned their place on the rails of Dover Street Market.

Her break away from pattern cutting may have launched her design career. But that background is what now sets her apart. Anyone who has tried on her immaculately tailored clothes will be able to appreciate her deep understanding of cut and silhouettes. "Louise always used to tell me, 'Don't just do what you want to do. You know what you're good at so focus on that'," she says. "That's the biggest lesson I learnt from her."

The Fashion and Freedom exhibition will be held at the Manchester Art Gallery from 13 May to 27 November. For more information, visit Manchesterartgallery.org.

Interview by Jainnie Cho