Madureira's style combines Western comic book influences with aspects of Japanesemanga, and has been credited for helping the latter influence the American comic book industry.
At age 16, while still in high school, Madureira started at Marvel Comics as an intern, working under editor Danny Fingeroth. His first published work was an eight-page story for the anthology series Marvel Comics Presents, starring Northstar. He became the regular penciler on Uncanny X-Men in 1994 . During the "Age of Apocalypse" storyline all X-Men titles were renamed; Madureira illustrated Uncanny X-Men's replacement as the four issue miniseries Astonishing X-Men, Vol. 1
He left Uncanny X-Men in 1997 to work on his own sword and sorcery series Battle Chasers for Wildstorm Comics' creator-owned Cliffhanger imprint (before it was sold to DC Comics). Shortly before leaving Uncanny X-Men, he commented that he felt the series had become too "dark and depressing" for his taste.