In 1999 she formed a pop group Z-1 with Mami Nejiki, Mai Fujiya, and Manami Nishiwaki. Although the group disbanded quickly, Aya Ueto decided to pursue a solo career and was signed to Pony Canyon. In 2002 her first single "Pureness" charted on the Oricon charts at #4.
The year 1999 is also the year that Aya Ueto entered the film industry with the film Killer of Paraiso. She would go on to have an extensive filmography, filming several TV dramas and movies.