Dame Trelise Cooper, born Trelise Neill, grew up in Henderson, West Auckland. She left school at 15, married at 17 and ran a building business with her first husband before the marriage ended when she was 21.
Her beginnings were modest. Her first childhood home, in 1960, was a state house in Ōtara; her father, Joe Neill, worked in the building trade. "I wasn't born with a silver spoon in my mouth," she told the New Zealand Woman's Weekly in 2025. "I was a kid who left school at 15 with a School Certificate from Henderson High School. I wasn't trained. I started in my kitchen with a pattern maker."
Her design business began in the early 1980s, and her first boutique opened in 1985. After a break to have a child, she returned in 1996 and built one of New Zealand's most recognisable fashion houses. Her designs have appeared in Vogue, Marie Claire, Women's Wear Daily and InStyle, as well as in Sex and the City.
The business grew to encompass several lines: Trelise Cooper, Cooper by Trelise, COOP, Board Room and Trelise Cooper Kids, all shown at New Zealand Fashion Week. She added an interiors fabric range with the textile house Charles Parsons and, in 2009, a fragrance, Trelise, composed by perfumer Yves Dombrowsky. In March 2009 she became the first New Zealand designer to stage a show aboard the Queen Mary 2. By 2016 the label had ten boutiques and more than 200 stockists across Australasia, Asia, Europe, the Americas and the Middle East. Her customers have included Julia Roberts, Liv Tyler and Stevie Nicks.
Colour is the house signature. "When you wear colour people notice and people comment," she told Metropol in 2020. "Those compliments become addictive." Even so, every garment is offered in black, she has said, for New Zealanders. Travel to Morocco, India, Greece and Mexico finds its way into her collections through colour, texture and pattern, and she describes her aim as capturing the strength and softness of women at once. Since 2008 the label has also produced an eco shopping bag that has sold in the millions. Her clients have also included Catherine Zeta-Jones. Of the business, she is philosophical: "I've been through many cycles of recessions and know that they pass."
Cooper has long been involved in charitable work, as patron of the Breast Cancer Research Trust, an advocate for domestic-violence awareness and a supporter of Habitat for Humanity, for which she staged an on-site house build at New Zealand Fashion Week in 2009. More recently she has championed the children's charity Variety, out of a conviction that children "are the currency for our future". The Trelise Cooper Kids flagship won the supreme award at the 2007 New Zealand Retail Interior Design Awards.
She was appointed a Member of the New Zealand Order of Merit in 2004 and elevated to Dame Companion in 2014. In 2015 her work entered the collection of the New Zealand Fashion Museum, and in 2018 she was inducted into the New Zealand Business Hall of Fame.