He was a member of Weapon X, formed by Professor Andre Thornton aka "The Professor" and also composed by Sabretooth, Lady Deathstrike and Omega Red.
At first, with his companions he tries to capture Hulk and Wolverine, after a fight against the clawed mutant, Bruce Banner gets mad, becoming the Hulk. At some point in the fight, Hulk chases Wolverine, as they still had a score to settle. When Wolverine runs away, and also Deadpool joins to flee with him having realized that the Hulk is more of a threat.
To stop the green monster, Deadpool throws him a grenade but this angers Hulk and Wolverine said that Hulk was Deadpool's to handle. Wolverine grabbed Deadpool and threw him at the giant. Deadpool tried to appeal to his "friend" to no effect.
Due to his healing factor, he survived to the explosion caused by Hulk only to be crushed by him at the end. His whereabouts afterwards are currently unknown.
Unlike most versions, this Deadpool not only works for Weapon X, but is devoid of some of his redeeming traits. Not only is he more sadistic than normal, but he even jokes about killing babies. Despite this, he does show off his more comedic side meaning he is mostly played for laughs.
Deadpool's Team X costume
Deadpool was scheduled to return in the second season of Wolverine and the X-Men before it was cancelled.
This version of the character constantly jokes around, much to the annoyance of others (especially Omega Red, Wolverine and even the Hulk) and shows characteristics similar to that of the comics, especially his early appearances in which he rarely, if ever, broke the fourth wall, a trait the character became known for in the early 2000s onwards.