[5] He primarily drew covers, posters and pin-ups for Spanish translated editions of Marvel Comics, published at the time by Planeta under the imprint called Cómics Forum.

[14] Pacheco later teamed up with writer Rafael Marín to create the characters Iberia Inc. and Tríada Vértice, two groups of Spanish superheroes, that starred in two miniseries published by Planeta-DeAgostini Comics under the imprint called "Línea Laberinto", with plots by Pacheco and Marin, script by Marin and art by Rafa Fonteriz (in Iberia Inc.) and Jesus Merino (in Tríada Vértice).

[13] Pacheco first got attention in the United States for his work as penciller on Dark Guard, a four-issue Marvel UK title, and the first book he fully drew by himself,[2][5] That assignment teamed him with writer Dan Abnett and inker Oscar Jimenez.

This led to his international career, which began in 1993,[10] when he was offered the art duties on Marvel Comics' Bishop miniseries, which was published in 1994, and which teamed him with writer John Ostrander and inker Cam Smith.

Shortly after this Pacheco became penciller on Marvel's Fantastic Four for two issues (#415–416), where he worked with writer Tom DeFalco as the title wrapped up in preparation for the "Heroes Reborn" storyline.

Pacheco's next assignment was in 2000, a four-issue Inhumans limited series, co-written with Rafael Marín with pencils by José Ladrönn and Jorge Lucas.

In 2003 Pacheco reunited with his Avengers Forever collaborator Kurt Busiek for the creator-owned fantasy war series Arrowsmith, published by WildStorm.

[20] The two told a tale in which, due to the time-traveling machinations of the Legion of Super-Villains, Batman and Superman took over the world and a group of Freedom Fighters has to rise up against them.

Later that year at DC, Pacheco shared alternate monthly pencilling duties with Ethan Van Sciver on the new Green Lantern series written by Geoff Johns.

Due to the difficulty of drawing twelve issues a year, the final chapter of their "Camelot Falls" story arc appeared in Superman Annual #13 (January 2008).

[13] In 2008, Pacheco produced covers for DC's weekly series Trinity, featuring Batman, Superman and Wonder Woman, and assisted artist J. G. Jones in illustrating the 2008-09 miniseries Final Crisis, on issues #4 to #6.

[9] In September 2022, Pacheco announced his retirement, and tweeted his final comics work, the cover to Damage Control (Vol 4) #2, which featured the characters Ant-Man and Wasp.

After consulting with Pacheco's family, Ruiz Boi also decided to create a funeral chapel in the plenary hall of the Palacio de los Gobernadores (Palace Of The Governors), at which the public would be able to pay their respects.

Likewise, a burning chapel is going to be set up in the Palace of the Governors so that all the people who wish to can pay homage to him… Our sadness is only lessened by the knowledge that in life, he achieved the recognition of all around him, that he knew and appreciated it.