Ashley left Singapore in 1996 to take a pattern cutting course at the London College of Fashion, and was later accepted into the prestigious Central St Martin's College in London after he managed to impress the interviewers with his portfolio. Ashley also moved to Middlesex University afterwards, but left before completing his degree.
He set up his own label "Ashley Isham" in 2000. In 2001, he also opened a boutique called Acquaint, hoping to "promote fashion talent and support other young designers", quoted from his website. He first attracted media attention as the desiger of the outfit worn by Zara Phillips at Royal Ascot in 2002, and rose to international fame after showing his Autumn/Winter 2003 collection during the London Fashion Week. Following this, he opened his flagship boutique, Ashley, in 2005.