The local town drunk of Woodbury and a former army medic, who descended into alcoholism before the zombie apocalypse. After the apocalypse, Bob was one of many survivors to join The Governor's settlement in Woodbury. His frequently drunken state worried many in the community, apparently even The Governor himself, as he was encountered by the man outside of his apartment and on the streets. His minor role in the story-line expanded significantly when he became the person responsible for saving The Governor's life. He was called upon by Gabe and Bruce Cooper to save The Governor when Alice and Dr. Stevens, the only town medics, had deserted the town. His summoning was due to Michonne's torture of him, nearly to the point of death. Bob was successful in saving The Governor's life, much to The Governor's own disbelief. After a slow recovery, The Governor personally asked him to watch over his undead daughter until he and The Woodbury Army returned from eliminating The Prison's survivors.
Obviously much has changed in the translation from comic book to TV screen, so a lot of what you read above won't be happening in the TV series, given what's already happened.
Although The Walking Dead creator/executive producer Robert Kirkman, did share the following in a piece I posted yesterday:
"Bob Stookey is very much the character that he was in the comic series. He also appears in the novel series and is a pretty big character there as well. Maybe that means we're adapting some of the stories he was involved in, maybe we're doing some other things he was a part of or maybe we're going a different way [...] Bob will be someone who is familiar to the comic and novel audience but we're definitely not married to doing those stories and could do different things there."
Oh, and by the way, in the comics, Stookey is a late 50's to early 60's white man. So, clearly the show's producers are taking creative license with the character. However, I'm sure that won't stop certain fans from from crying about the race-switch.
Entertainment Weekly has your first look at Gilliard as Stookey below: