Aja obtained a degree in Fine Arts at the
University of Salamanca and served as a member of the faculty of fine arts from 1995 to 2000. He began working as a professional illustrator in
Barcelona in 2000. He has conducted public lectures on illustration as Faculty of Fine Arts at both Universidad de Salamanca and
Universidad Complutense de Madrid (UCM). His work includes
CD covers, as well as
computer graphics with collaborator
Marcel·lí Antúnez Roca. In November 2006, Aja and writers
Ed Brubaker and
Matt Fraction started the series
The Immortal Iron Fist. In 2011 Aja provided art for
David Lapham's
Wolverine: Debt of Death one-shot. In August 2012 he started a new
Hawkeye series with writer Matt Fraction, as part of
Marvel NOW!. The series was released to positive reviews, with critics praising the storyline and art styles. As artist on
Hawkeye, Aja won the 2013
Eisner Award for Best Penciler/Inker (tying
Chris Samnee) and won the 2013
Eisner Award for Best Cover Artist.
Hawkeye won the 2014
Eisner Award for
Best Single Issue (Or One Shot) and Aja again won the Eisner Award for Best Cover Artist for his work on the series. This would also be his first work for DC. ==Personal life==