Origin
Nothing is known about the person that Zombie was before he became reanimated and was recruited for SHIELD. The organization was however trying to find this out.
Creation
Zombie (John Doe) was created by Keith Giffen and Eduardo Franciso and first appeared in Nick Fury’s Howling Commandos issue 1 (2005). He is not to be mistaken for the more well-known Zombie, Simon Garth.
Major Story Arcs
Howling Commandos
Zombie was recruited into the Howling Commandos, a team of supernatural monsters that became a special task force for SHIELD. Zombie had a number of missions with the team before they disbannded.
More recently, a new team of Howling Commandos was created by SHIELD. Zombie John Doe was not part of the line-up.