Lobdell began reading comics at 17 and started his writing career in college. He became known for his work on Marvel Comics' X-Men-related titles in the 1990s, including Uncanny X-Men, Generation X, Excalibur, and X-Factor. Lobdell wrote for other Marvel series, such as Daredevil, Alpha Flight, and Iron Man, and addressed the HIV/AIDS epidemic through the Northstar character's coming out storyline. He returned to Marvel in 2001 and worked on other projects like Stan Lee's Mosaic and the Galaxy Quest series. Lobdell wrote for DC Comics, including Red Hood and the Outlaws, Teen Titans, and Flash Forward, but faced criticism for his portrayal of Starfire/Koriand'r. He has won industry recognition, including a nomination for the Comics Buyer's Guide Award for "Favorite Writer" in 1997. Lobdell faced controversy for a Twitter incident with Ron Marz and for sexually harassing comic book artist/writer MariNaomi during a panel at Long Beach Comic Con.
