Deadpool first appeared in The New Mutants #98 in February 1991. Rob Liefeld came up with the character's design and name while Nicieza came up with Deadpool's speech mannerisms. Liefeld, who was a fan of Teen Titans, showed the character to Fabian. Upon examination, Nicieza told Liefeld that "he was Deathstroke from Teen Titans", and gave him the real name of "Wade Wilson" as a reference to Slade Wilson, aka Deathstroke. Yet another inspiration to Deadpool was Spider-Man, who would make jokes during fights as well.
In his first appearance, Deadpool is hired by Tolliver to attack Cable and the New Mutants. After subsequently appearing in X-Force as a recurring character, Deadpool began making guest appearances in a number of different Marvel Comics titles such as The Avengers, Daredevil, and Heroes for Hire. In 1993, the character received his own miniseries, titled The Circle Chase, written by Fabian Nicieza and pencilled by Joe Madureira. It was a relative success and Deadpool starred in a second, self-titled miniseries written in 1994 by Mark Waid, pencilled by Ian Churchill, and inked by Jason Temujin Minor and Bud LaRosa. Waid later commented, "Frankly, if I'd known Deadpool was such a creep when I agreed to write the mini-series, I wouldn't have done it. Someone who hasn't paid for their crimes presents a problem for me."
In 1997, Deadpool was given his own ongoing title, initially written by Joe Kelly, with then-newcomer Ed McGuinness as an artist. Deadpool became an action comedy parody of the cosmic drama, antihero-heavy comics of the time. The series firmly established his supporting cast, including his prisoner/den mother Blind Al and his best friend Weasel. The ongoing series gained cult popularity for its unorthodox main character and its balance of angst and pop culture slapstick and the character became less of a villain, though the element of his moral ambiguity remained. The writer Joe Kelly noted, "With Deadpool, we could do anything we wanted because everybody just expected the book to be cancelled every five seconds, so nobody was paying attention. And we could get away with it." Reportedly Kelly introduced the fourth wall breaking gimmick.
The series was taken over by Christopher Priest who noted that he found Kelly's issues to be "complex and a little hostile to new readers like me" and that by issue 37, he realized that "it was okay to make Deadpool look stupid."
Deadpool lasted until issue #69, at which point it was relaunched as a new title by Gail Simone with a similar character called Agent X in 2002. This occurred during a line wide revamp of X-Men related comics, with Cable becoming Soldier X and X-Force becoming X-Statix. Simone notes that 'When I took the Deadpool job, the revamp hadn't been planned, so it was a complete surprise. Thankfully, we heard about it in time to make adjustments to the early scripts'. It appeared that Deadpool was killed in an explosion fighting the supervillain Black Swan. Deadpool's manager, Sandi Brandenberg later founded Agency X with a mysterious man called Alex Hayden, who took the name dubbed Agent X. Deadpool later returned to the series. Simone left the title after seven issues due to creative differences with the series editor, but then returned to conclude with issues 13-15
Deadpool's next starring appearance came in 2004 with the launch of Cable & Deadpool written by Fabian Nicieza, where Deadpool became partnered with his former enemy, Cable, teaming up in various adventures. This title was canceled with issue #50 and replaced by a new Cable series in March 2008. Deadpool then appeared briefly in the Wolverine: Origins title by writer Daniel Way before Way and Paco Medina launched another Deadpool title in September 2008. Medina was the main series artist, with Carlo Barberi filling in on the first issue after the "Secret Invasion" tie-in.