Ciruelo was born in Buenos Aires, Argentina on July 20, 1963. His formal art training was limited to a few courses in drawing and advertising design, after which, at the age of 18, he found work at an ad agency as an illustrator. At 21 he became a freelance illustrator and has never looked back.

In 1987 Ciruelo traveled to Europe and settled in Spain. He then embarked on a search for publishers for his "worlds of fantasy," eventually finding them in Spain, England, the United States and Germany. Ciruelo continues to work for U.S. publishers, among them Bantam, for whom he did book covers for the trilogy written by George Lucas, Chronicles of the Shadow War. He has also created a number of rock album covers, including The 7th Song and The Elusive Light and Sound from Steve Vai. Ciruelo’s clients include Wizards of the Coast, TSR, Berkley, Tor Books, Warner, Ballantine, Heavy Metal magazine, and Playboy magazine.

Ciruelo’s art is regularly featured in the prestigious annual collection Spectrum: The Best in Contemporary Fantastic Art and he comes out with a yearly dragon calendar. Currently, he is writing and illustrating Fairies and Dragons, which is also being considered for film adaptation. Ciruelo lives with his wife Daniela and their kids, Angelo and Lys, in Sitges, a quaint and magical town near Barcelona, on the shores of the Mediterranean Sea.