Gallagher moved to
New York City and established "Katie Gallagher". She moved to the
Chinatown area of
Manhattan. Gallagher began work on her SS10 (spring/summer 2010) collection in anticipation of showing the apparel at
New York Fashion Week in September 2009. She made sketches and paintings to establish the design for the line prior to fabrication. The SS10 collection, entitled "Veil", was well received by the press. She submitted photos of the line to the
Ecco Domani Fashion Foundation for consideration in their 2009/2010 search for emerging designers. In January 2010, Gallagher was notified that she was a semi-finalist in the
Ecco Domani Fashion Foundation 2009/2010 search. Gallagher presented collections for SS10, AW10, SS11, AW11, SS12, and AW12 at New York Fashion Week. Her SS10 collection was called "darkly futuristic, sleek" in
Refinery 29. Considered "sporty yet aggressive", Gallagher's SS11 collection, "Arena", was inspired by athletics, in particular running. "Gris-Gris", her AW11 collection named after the voodoo talisman bag, featured "grays and blacks, asymmetries and paradoxical volumes", and "heavily blackened eyes, and a cyborg-esque eye detail". Detailing included makeup inspired by the bloodstream, and hair inspired by the heart. Selected designs from Katie Gallagher's work have been pulled, borrowed for editorial shoots, by
Daphne Guinness, and on a continuing basis by
Lady Gaga's stylist,
Nicola Formichetti. The list of stockists for the Katie Gallagher line has grown to include high-end stores around the world. In explaining her method of designing, Gallagher said, "Everything I make starts with my paintings, which I've done every season prior to construction. I love to try to re-create a three-dimensional version of whatever I've drawn; it requires pretty unconventional pattern-making." On November 5, 2012, Gallagher launched the Katie by Katie Gallagher
diffusion line of clothing that includes both separates and jewelry pieces. ==Death==