Mark Bagley was born to a military family in Frankfurt, Germany. He had always wanted to break into the comic book business. At age 18, he joined the military so that he could qualify for the G.I. Bill and go to art school.
After his work in the military and art school, he continued trying to break into the comic industry but ended up working for Lockheed Martin making technical drawings.
Later in life, he fathered a child, a daughter named Angela, who is a teacher.
In 1983, Marvel Comics Editor-in-Chief Jim Shooter created the Marvel Try-out Book to draw new talent into the comic book industry. The contest involved a deconstructed comic book in which contestants could complete the comic and submit it to Marvel. The winner would be awarded a professional assignment with Marvel.
At 27 years old, Mark Bagley entered the contest and won first place for penciling. This led to a series of low profile penciling jobs including jobs for Marvel's New Universe line and backup stories in Captain America. A majority of his work during this time was for the first series of Marvel Universe Trading cards.
In 1990, Tom DeFalco and Ron Frenz created a team of teenage superheroes called the New Warriors. Given the positive fan reaction, Marvel created a new series based on these heroes and assigned Bagley and Fabian Nicieza to the title.
Though not an instant success, the title rose in fame to become one of Marvel’s more successful titles in the 1990s.
A couple of years into the New Warriors run, New Warriors editor Danny Fingeroth became responsible for the Spider-Man line of titles. At the same time, Erik Larsen vacated his spot as penciler on Spider-Man’s flagship title Spider-Man illustrated by Mark BagleyThe Amazing Spider-Man.
Fingeroth decided to take a chance on Bagley, who was a relatively inexperienced artist to be assigned what is arguably Marvel’s flagship title. After a rough start, Bagley hit his stride on The Amazing Spider-Man and eventually grew to be considered the definitive Venom illustrated by Mark BagleySpider-Man artist of the mid-1990s. His artwork was used extensively for licensed material, appearing on everything from plates and cups to credit cards.
Bagley also holds the distinction of being the artist on Marvel’s first web-based comic book, featuring Spider-Man, which appeared on Marvel’s official website.
After working on Spider-Man for several years, Bagley began to feel burnt out on Spider-Man. Needing a change, he next collaborated with writer Kurt Busiek on a new team of superheroes, the Thunderbolts. The concept behind the Thunderbolts was that of a team of super villains who posed as superheroes in order to gain the public’s trust. As the title progressed, some of the villains began to realize they enjoyed the role of a hero and no longer wanted to be villains.
The title enjoyed modest success and though its sales did decline over time, the decline was so slow and the fan base was so dedicated that the title continued to be published even after Bagley left the title in 2001 (at issue #50).
Bill Jemas, publisher at Marvel in the year 2000, was looking to relaunch Marvel’s primary franchises in a way that would make them accessible to younger readers. Designed as a six-issue mini series, Ultimate Spider-Man would be a title that began the Spider-Man mythos from the beginning set in modern times. Marvel wanted Bagley on the title from the beginning, but, still being burnt out from his earlier run, he resisted.
Eventually though, he (reluctantly) agreed and was assigned Ultimate Spider-Man with writer Brian Michael Bendis. The title was an instant hit and soon turned from a limited series to an ongoing series by Bendis and Bagley.
They went on to enjoy the longest continuous run of any creative team on a mainstream Marvel superhero comic beating the record set by Stan Lee and Jack Kirby with Ultimate Spider-Man #103 (published in December 2006). He eventually left the title after #111 was published in July 2007.
Bagley collaborated again with Bendis on the latter's second story arc of Mighty Avengers. That was his last work for Marvel before he becomes exclusive to DC Comics.
It was reported in January 2011, that starting with issue 156 of Ultimate Spider-Man, Bagley will reunite with longtime collaborator and writer Brian Michael Bendis for an eight issue story arc entitled 'Death of Spider-Man' which will prelude in February and kicks in with the actual storyline in March and will conclude in July 2011.