According to Deep Impact writer Bruce Joel Rubin, a Disney production president took notes during a lunch conversation about his script and used them to initiate Armageddon as a competing film.

Nine writers worked on the Armageddon script, though only five received credit: Robert Roy Pool, Jonathan Hensleigh, Tony Gilroy, Shane Salerno and J. J. Abrams, while uncredited contributors included Paul Attanasio, Ann Biderman, Scott Rosenberg and Robert Towne.

Bruce Willis was cast as part of a three-picture deal to compensate the studio for the failed 1997 film Broadway Brawler, and he took a significant pay cut for the role.

Sean Connery was originally considered for the role of Harry Stamper, but director Michael Bay chose to cast a younger actor after meeting real oil drillers.

Bradley Cooper auditioned for the role of A.J. Frost, which ultimately went to Ben Affleck.

Principal photography ran from August 27, 1997 to January 29, 1998 at Culver Studios in Culver City, California, and the film had a $140 million budget, making it Disney's most expensive film at the time.

In May 1998, Disney chairman Joe Roth added $3 million to the budget for extra special effects scenes by Dream Quest Images depicting an asteroid hitting Paris, footage inserted just two months before release specifically to visually distinguish the film from Deep Impact in TV ads.

After filming wrapped, Home Improvement star Tim Allen got permission from Michael Bay (via ABC executive Bob Iger) to use the leftover asteroid set as a gag in the show, appearing as a fake cave in Wilson's basement, though Bay required a six-month wait after the film's release.

Following the September 11 attacks, ABC censored the scene depicting the World Trade Center being hit by meteors when airing the film in 2002 due to its resemblance to the real attacks.

After the 2003 Space Shuttle Columbia disaster, screen captures from the film's opening scene showing Atlantis's destruction were falsely circulated as real satellite images of the accident, prompting FX to pull the film from its schedule and air Aliens instead.

Roger Ebert named Armageddon the worst film of 1998, giving it one star, while his At the Movies co-host Gene Siskel gave it a Thumbs Up.

A 2011 study by four physics postdoctoral students, later reported by The Daily Telegraph, calculated that splitting the asteroid as depicted would require an H-bomb a billion times stronger than the Soviet Union's 'Big Ivan,' the most powerful bomb ever detonated on Earth.

On the film's commentary track, Ben Affleck recalled asking Michael Bay why it was easier to train oil drillers to be astronauts than to train astronauts to be drillers, to which Bay simply told him to shut up.