Day used Kate Moss as the model in an eight-page fashion story for The Face, in July 1990. The story showcased garments by Romeo Gigli, Joseph Tricot, Ralph Lauren, and a feather head-dress from the now-defunct Covent Garden boutique World. The photographs, which include one depicting Moss topless and another in which it is implied that she was naked, are some of the first published fashion photographs of Moss, who was sixteen at the time (since 2003, following the Sexual Offences Act, designates that those under eighteen are protected and defined as children).
In 2006, Day had a solo exhibition of her photographs at Gimpel fils gallery in London.
In 2007, Day was commissioned to photograph Kate Moss by the National Portrait Gallery. Discussing the shoot, Day Said, "I suggested to Kate that we have a conversation about a serious subject. The subject she chose to talk about revealed her true feelings and in turn defined her character."
Moss and others, raised more than £100,000 by selling photographic prints—in a campaign they titled 'Save the Day'—in order that Day receive Insulin Potentiation Therapy Low Dose or IPTLD chemotherapy in Arizona, USA. Day returned to England where, from February 2010 until her death on 27 August 2010 from complications related to the tumor, she was "gravely ill".
Writing in The Daily Telegraph, in late August 2010, Belinda White said, "Corinne opened the door for a whole generation of photographers, designers, models and stylists who suddenly saw that the fashion industry didn’t have to be this exclusive club for the privileged and perfect."