"It's something that I've gotten used to, it happens from time to time on the show," Kirkman said on live after show Talking Dead.
"Really if anything, it just makes me more excited. I think that any time that path is not set, any time you can't look at a comic book series and go, 'oh, I know exactly what's going to happen,' it makes things a little bit more exciting," Kirkman added.
"And dealing with those unknowns, when we're in the writers room, when we're working on season 9, all those changes that kind of snowball out from that, it just makes for a better show."
Carl is still alive in Kirkman's ongoing monthly comic book series where the one-eyed teen plays a pivotal role as the future successor of Alexandria leader Rick Grimes.
The Walking Dead television series killed Carl in last Sunday's mid-season premiere, "Honor," marking arguably the biggest deviation yet from Kirkman's black-and-white comic book.
"From the very beginning, Robert said, 'Look, these are two different types of media,'" executive producer Gale Anne Hurd said during our May 2017 visit to The Walking Dead set.
"Because we have characters that were never in The Walking Dead comic, like Daryl Dixon, that automatically changes that dynamic. He basically said, 'If this was a panel-by-panel adaptation, it would be a different thing.'"
Despite some of The Walking Dead's biggest change ups from page to screen, Hurd said changes aren't made for the sake of change.
"Is there a bit of, 'Yeah, we don't want people to know exactly what's going to happen?' Sure," Hurd explained. "It makes for better drama. But there's not a conscious intention to say, 'Okay, they did it this way in the comic, how can we specifically do this differently?'"
Chandler Riggs' Carl Grimes is just the latest character to suffer a fate that differs from their comic book counterpart, and his death is but one of several major changes shambling towards The Walking Dead.
Jeffrey Dean Morgan, who plays bat-wielding villain Negan, said he will "forever be disappointed" over the loss of Carl.
That major change prevents the television series from adapting the unique relationship formed between Carl and Negan in the comics, explored in depth in the books following the conclusion of the All Out War storyline.
The Walking Dead airs Sundays at 9/8c on AMC.