In January 2010, AMC formally announced that it had ordered a pilot for a possible series adapted from The Walking Dead comic book.

"Days Gone Bye" was heavily promoted in the months preceding its release; as part of an expansive advertising campaign, zombie invasion events were coordinated in selected locations including New York City, Washington, D.C., London, and Madrid.

The episode opens in medias res as former Sheriff's Deputy Rick Grimes (Andrew Lincoln) scavenges for gas and supplies at an abandoned convenience store on a deserted highway in rural Georgia.

Returning to several weeks prior, Rick is seriously injured while chasing down criminals alongside his partner and childhood friend Shane Walsh (Jon Bernthal); he is shot in the shoulder and goes into a coma.

When he regains consciousness, he finds the hospital abandoned and horrifically ransacked: the walls are sprayed with blood, destroyed equipment is everywhere, and dead bodies litter the hallway.

He walks past a set of double doors secured with heavy chains and spray-painted with the ominous warning "Don't Open Dead Inside".

In his interview, Kirkman exclaimed that it was "an extreme validation of the work", and continued by expressing that "never in a million years could [he] have thought that if Walking Dead were to ever be adapted that everything would be going this well.

"[3] On January 20, 2010, AMC officially announced that it had ordered a pilot with Darabont and Hurd acting as executive producers; the former wrote the script and directed the episode.

[6] Upon reading the script, Robert Kirkman thought that producers were consistent with his comic, adding that they could possibly improve his initial work.

In an interview with MTV News, special effects artist Greg Nicotero stated that while anyone was welcome to audition, the producers of the show were looking specifically for people who possessed exceptional height and thin features.

"[10] Alongside with Frank Darabont, Nicotero had previously collaborated with Romero on several occasions, and looked at the structure of the zombies in his films for inspiration.

[12] While Gale Anne Hurd didn't expect to cast Lincoln, Robert Kirkman was ecstatic with his acting, evaluating him as an "amazing find".

"[10] Shortly after the announcement, Sarah Wayne Callies was approached to play the role of Rick's wife Lori Grimes, the lead female.

[13] "Days Gone Bye" featured guest appearances from actors and actresses such as Emma Bell (Amy), Andrea's younger sister.

[31] The producers chose to film in Atlanta because of its proximity to Cynthiana, Kentucky, Robert Kirkman's hometown and the setting of his comic's first issue.

He stated, "I tagged along on a location-scouting expedition, and that was pretty fun—watching Frank Darabont walking through the streets of Atlanta as if he owned the entire city, daring cars to hit him.

"Days Gone Bye" premiered in Hong Kong on TVB Pearl on August 30, 2011,[44] while it expanded in international markets during the first week of November.

[51] "Days Gone Bye" became the highest-rated cable telecast ever, hitting significantly higher numbers than predecessors Swamp People and Ice Road Truckers on the History Channel.

[54] "Days Gone Bye" garnered the highest total viewership for a season premiere out of any cable program up until the airing of its successor, "What Lies Ahead", which attracted 7.3 million viewers.

"[51] Senior Vice President Joel Stillerman ascribed that much of its success came from the storytelling presented in the episode; "The Walking Dead is that rare piece of programming that works on so many levels.

"[51] And there's no underplaying the role of AMC, too, which is creating a distinctive brand out of very different series such as Mad Men, Breaking Bad, Rubicon, and now The Walking Dead.

The site's consensus reads: The Walking Dead's debut delivers intense horror set apart by its focus on tragedy and the human condition—not to mention awesome zombie kills.

"[63] St. Louis Post-Dispatch's Gail Pennington appraised "Days Gone Bye" as "genuinely terrifying", adding that despite being too gruesome for her tastes, it was "too engrossing not to watch.

"[64] In an A− grade review, Boston Herald journalist Mark Perigard said that the pilot episode was a "suspenseful thriller",[65] while Robert Bianco of USA Today avouched that it was "one killer of a zombie show.

"[66] The Wall Street Journal writer Nancy deWolf Smith felt that "Days Gone Bye" contained a cinematic quality to it; "The pilot episode [is] so good that it has hooked even a zombie hater like me.

"[59] Liz Kelly and Jen Chaney of The Washington Post reacted positively to the series premiere, deeming it as a "chilling show", and exclaiming that it had a "very real sense that the world can go completely mad, and stay that way for good.

[74] James Poniewozik of Time reacted positively to the episode, exclaiming that it "paints a thoroughly convincing postapocalyptic world, both visually and emotionally.

He wrote: "The Walking Dead draws the audience in almost instantly with its cinematic 90-minute pilot, then incorporates tasty soap-like elements meant to animate the ensuing episodes.

"[69] Gilbert referred to his accent as "spotty",[59] while Goldman professed that Lincoln fit into character very well; "For much of the pilot, he's on his own and exudes a lot of believable, shocked emotion, as Rick tries to process what he is seeing.

Specifically, the episode included a near shot-for-shot remake of Rick Grimes searching for supplies among abandoned cars, though in this case, with Carl in his shoes.