But now she has become what is believed to be the first globally-recognised fashion designer to design a school sports uniform.
And not just any old school sports uniform - one that appears to bring good luck to the wearer.
She designed new netball and hockey uniforms for Columba College. The school's 1st XI hockey team has won its three games this season.
''I think the new uniform might be lucky,'' she quipped.
Ms Cooper said she was asked to create the uniforms because of her connection to the school.
Her 10-year-old son Hugo is a pupil in Columba College's junior school and her 4-year-old son Louis will start next year.
''I've never designed a sports uniform before.
''I was pleased to be asked, but it was a little bit scary because it was a new challenge, a diversification of what my core business is.''
She created three designs, based on elements of the school's colours and tartan, and was careful to include the school's logo - a dove.
They were then shown to the pupils who voted for their preferred design.
''I did one that was quite fashiony, but it probably wasn't the most practical for the court.
''It's really great that Columba College have asked a local designer to do this because I think that using a local designer gives the uniform a practical design edge and makes it distinctive.''
Columba College 1st XI hockey team captain Phoebe Steele (16) agreed, saying she was delighted with the practicalities of the new uniform.
''I like the material. It's really light, cool and nice to play in.''
Columba College Senior A netball team centre Analise Cowie (15) liked the dove logo and the school tartan on the uniform.
''You know instantly that it's Columba College.''
