Rooker's big-screen debut came in 1986, when he played the twisted title character in "Henry: Portrait of a Serial Killer."
In "Walking Dead," Rooker's Dixon was at first polarizing and then beloved as he consistently put family first, until that mindset got him killed (by a human, not a zombie).
Despite the science-fiction tag that accompanies "Walking Dead" and his upcoming role in "Guardians of the Galaxy," the morals and themes behind Rooker's characters make his work "much more believable than a lot of other stuff that other people do," he said.
The adoration for Dixon (and Rooker himself) at Wizard World Comic Con stops across North America has been "absolutely through the roof," Rooker said.
Many Dixon tribute videos have been uploaded to YouTube since the character died in the penultimate episode of season three. Rooker said that Dixon "has made an indelible mark on this series. No matter how many seasons this series goes, I think everyone will remember Merle Dixon."
Military personnel and law enforcement in particular are big Rooker fans, as they can relate to the commitment and brotherhood he often portrays on screen.
"Because Merle Dixon . . . paid the ultimate price to help his brother survive in this new world, every marine in the world gets it," Rooker said. "That's what they do every day in real life."
In addition to occasionally playing detectives and soldiers, Rooker has been involved with the "Call of Duty" video-game series. Fittingly, he played himself in the "Call of the Dead" mode in 2010's "Call of Duty: Black Ops," in which players try to fend off waves of zombies for as long as possible. His voice can be heard as Michael Harper in "Call of Duty: Black Ops II," as well.
A "bad ear" kept Rooker out of the military as a teenager, but he still reveres that line of work.
"I love these guys and I love their commitment and what they have done for our country and what they are still doing for our country," Rooker said.
When he appears at the Wizard World Philadelphia Comic Con June 19 through 22, Rooker said, he expects that some visitors will approach apprehensively, fearful from some of the dark and sinister roles he has played.
"Once they come up and greet me and I greet them," he said, "they're like, 'Oh, this guy isn't so bad after all.' "
An actor can wear many faces, but Rooker said he is a family man who would give his life for his wife and two daughters - not unlike Merle Dixon.
"I'm amazed and dumbfounded at times because what I do, it's such an interesting job," he said. "I'm bringing something to life from the page and making people believe it."
For info and tickets to Wizard World Philadelphia Comic Con (June 19-22 at the Pennsylvania Convention Center, 1101 Arch St.), go to wizardworld.com/philadelphia.