In 2000, Treacy became the first milliner in eighty years to be invited to exhibit at the Paris haute couture fashion shows.

Philip Anthony Treacy was born on 26 May 1967 in the small village of Ahascragh, near Ballinasloe, in County Galway in the Republic of Ireland, whose population was circa 500.

[1][3] Treacy says that his interest in sewing started at age five,[4] and that his obsession with the weddings in the Catholic church across the road from his house inspired an early passion for fashion.

[5] In 1985, at age 17, Treacy moved to Dublin to study fashion at the National College of Art and Design, where he spent a six-week work experience with British milliner Stephen Jones, and graduated in 1987.

[6] In 1988, Treacy won an MA scholarship for the Fashion Design course at the Royal College of Art in London, and graduated in 1990 with first class honours.

Everyone was boring in comparison to her.In 1991, aged 23, Treacy got his "big break" when asked by Karl Lagerfeld to come to the Chanel showrooms in Paris for what was to be the start of a long-term working relationship;[2] the meeting was held on the prompting of Blow.

[5] Two years later, Treacy held his first fashion show during London Fashion Week in Harvey Nichols, with Naomi Campbell, Yasmin Le Bon, Kate Moss, Christy Turlington and Stella Tennant modelling in return for keeping Treacy's hats, all of which were black.

[11][12][13] Treacy's first solo show in 1993 saw him debut on the fashion and celebrity radar when no fewer than five of the most famous supermodels of the era – Naomi Campbell, Yasmin Le Bon, Kate Moss, Stella Tennant, and Christy Turlington – appeared on his catwalk.

"The media went crazy when all those girls did my show, but it completely changed perceptions of the hat.Treacy has designed hats for Alexander McQueen (another discovery of Isabella Blow),[c] including his 1999 white collection for Givenchy in Paris, for Karl Lagerfeld at Chanel, and for Valentino, Ralph Lauren, Donna Karan, Versace and Rifat Ozbek.

[20] Lady Gaga described Treacy as "the greatest milliner of all time", while hosting his 2012 London Week fashion show.

[23][24] As well as Isabella Blow, Sarah Jessica Parker, and Lady Gaga, notable muses for Treacy's hats are socialite Daphne Guinness,[25] model Naomi Campbell,[2][26] and singer, and model, Grace Jones,[27] who used Treacy as art director and designer for her 2009 The Hurricane Tour.

[30] In a July 2018 Desert Island Discs interview on BBC Radio 4, Treacy said of the backlash to his design: "There was a moment where I thought I would find myself with my head on a spike outside the Tower of London".

[38][39] In July 2018, Treacy credited the patronage of Elizabeth II with "single-handedly saving the British hat industry".

The other designers were Paul Costelloe, Louise Kennedy, John Rocha, Lainey Keogh and Orla Kiely.

[51][52] Treacy is gay and in May 2017 he married his long-term partner of over 21 years, Stefan Bartlett, in a ceremony in Las Vegas.

[50][55] He is particularly close to his sister, Marion Tubbing,[50] the eldest sibling, whom he credits with supplying him with editions of Harper's and Queen and Vogue while living in Galway (Tubbing was working in London at the time),[54] and to whom, along with his partner Bartlett, Treacy dedicated his 2015 biography: Philip Treacy: Hat Designer.