The original air date, on ABC, was November 20, 1983. Over one hundred million Americans were estimated to have viewed the program. Still rated as the most watched television movie on U.S. television as of May 2017 (not including miniseries), it was watched by 38.55 million households, or forty-six percent, with a Neilsen share of sixty-two percent.

The premiere of this television movie was a major media event. No sponsors bought commercial time after the nuclear war broke out, so the last half was aired without commercials.

Nicholas Meyer claims he suffered severe flu-like symptoms throughout the making of this film. When doctors could find no reason for his illness, they eventually determined that Meyer was actually suffering from severe clinical depression, which Meyer attributes to having to face the horrors of nuclear war in such depth.

Immediately after the film's original broadcast, it was followed by a special news program, featuring a live discussion between scientist Dr. Carl Sagan (who opposed the use of nuclear weapons) and Conservative writer William F. Buckley (who promoted the concept of "nuclear deterrence"). It was during this heated discussion, aired live on network television, where Dr. Sagan introduced the world to the concept of "nuclear winter" and made his famous analogy, "Imagine a room awash in gasoline, and there are two implacable enemies in that room. One of them has nine thousand matches, the other seven thousand matches. Each of them is concerned about who's ahead, who's stronger."

When production began, the nuclear attack scene was longer and supposed to feature extremely graphic, yet very scientifically accurate, shots of what happens to a human body during a nuclear blast. Examples included people being set on fire, flesh carbonizing, being burned to the bone, eyes melting, faceless faces, skin hanging, deaths from flying glass and debris, limbs torn off, being crushed, blown from buildings by the shockwave, and people in fallout shelters suffocating during the firestorm. Also cut, were images of radiation sickness, as well as graphic post-attack violence from survivors such as food riots, looting, and general lawlessness as authorities attempted to restore order.

Director Nicholas Meyer fought network censors and the U.S. government so frequently about the film's content, particularly the violence, that he quit the production during the editing stages and threatened to petition the DGA to have his name removed. He eventually relented and returned to the production, but he vowed to never work in television again.

Before the film even aired, controversy arose over who attacked first: the U.S.S.R. or the United States. Nicholas Meyer wanted the answer to remain ambiguous, to focus on the horrors of nuclear destruction. He wanted the evil to be nuclear weapons in general, not government.

Unable to get permission to use U.S. Department of Defense stock footage of mushroom clouds (although able to get stock footage of Minuteman III ICBM test launches), producers were forced to re-create mushroom clouds using visual effects.

In 1983 two weeks before The Day After aired. Mister Rogers' Neighborhood (1968) aired a whole week of episodes titled "Conflict" It has been thought to be a direct response to the movie, to help any children who may have seen it cope with the violence portrayed. Yet this has been proven to be just a coincidence that the two aired so close to each other. Since the episodes of Mister Rogers, would have had to have been written and produced at least a year before The Day After was aired. Yet they both deal with the concept of war and nuclear bombs.

As the news gets worse, Steven Klein (Steve Guttenberg) hitchhikes home to Joplin. He is referring to Joplin, Missouri, the birthplace of bombardier Kermit Beahan, pilot of the B-29 Superfortress "Bockscar", which dropped the atomic bomb on Nagasaki, Japan. In Beahan's own words, "I hope to keep the dubious distinction of being the last man to use an atomic bomb."

ABC set up special 1-800 hotlines to calm people down during and after the original airing.

The tank that was used to created the "mushroom cloud" was the same tank that used to created the Mutara Nebula effect in Star Trek II: The Wrath of Khan (1982), which was also directed by Nicholas Meyer.

The mushroom clouds were created by injecting colored oil plumes into a tank of water (which accounts for the fact that the clouds are dark red, rather than a more realistic hue).

With the full support and encouragement of the city of Lawrence, Kansas, the filmmakers from ABC successfully transformed Lawrence into a nuclear wasteland for a few weeks, knocking out windows in storefronts downtown, placing burnt and overturned cars painted with clouds of black spray throughout the streets, covering the streets and sidewalks with rubble and bricks, and setting up giant "tent cities" and shantytowns down on the banks of the Kansas River, where the teeming homeless set up camp after the attack. Over two thousand Lawrence residents, including many University of Kansas students, were used as extras, and were paid fifty dollars to shave their heads bald and act as if they were dying of radiation sickness. They were asked not to bathe during the aftermath scenes to add authenticity to the movie.

To give the film a documentary feel, Director Nicholas Meyer wanted to cast complete unknowns. Jason Robards, Jr. was his only major star. Many others, including JoBeth Williams, John Lithgow, Amy Madigan, and Steve Guttenberg, went on to successful careers.

Because it was too expensive to destroy every window seen in after the blast and then replace it with a new one, a lot of windows were decorated with black paper to indicate broken glass.

Several visual effects scenes that were planned in the original script were scrapped when the production was cut from four hours to two and a half hours. Among the scenes that were scrapped were a bird's-eye view of the nuclear explosion over Lawrence, Kansas, witnessed from a 737 on approach. A simulated newsreel of tactical nuclear exchanges between NATO and Warsaw Pact forces in Germany was also scrapped.

The original title for the movie was "Silence in Heaven", which Meyer preferred to the title ABC selected, "The Day After".

In the U.S.S.R., the film was shown in the spring of 1987 (it was a warming period in Soviet-U.S. relations since the beginning of the Cold War). The film was shown in prime time in a thematic unit with Pisma myortvogo cheloveka (1986), which also touches upon the consequences of nuclear war.

The film was screened by then-President Ronald Reagan at the White House. While it's been confirmed that President Reagan and his senior staff were deeply moved by the film's depiction of a nuclear holocaust, other details involving Reagan and the film remain murky. One report that the movie was one of the driving factors behind the U.S. and the Soviet Union signing a majors nuclear arms-reduction treaty in Europe has been debunked because that treaty was already being worked on by the countries before this film premiered in 1983. Another story said that Reagan sent Nicholas Meyer a note saying "The Day After" was a factor in arms treaty decisions; Meyer said he never received that, but said that President Reagan did reach out to praise the film after seeing it.

The screenwriters chose to set the film mostly in Lawrence, Kansas, to dramatize how nuclear war would affect everyone. During the Cold War, it was theorized that Lawrence, Kansas would be one of the few cities completely unaffected by nuclear war, because it's near the exact geographic center of the continental United States.

When originally televised, the Presidential speech via radio was delivered by a voice actor who sounded much like Ronald Reagan. This speech was re-voiced by a different actor for the VHS/DVD releases and the version which airs on cable television. Conversely, a startling close-up of a screaming hospital patient was excised from the original ABC telecast, but restored for the home video and cable versions of the film.

The U.S. Department of Defense would only co-operate with the film's production on condition that it be made clear in the story that the Soviets, and not the United States, launched their missiles first.

The "General on board" was Clarence Rueben Autery, a real thirty-year U.S. Air Force decorated Vietnam veteran and commander of S.A.C.

One cut scene depicted two groups of students at the University of Kansas fighting each other over remaining food stocks. The first group comprised of student athletes, while the second group comprised of science students led by Professor Huxley (John Lithgow).

After watching this, President Ronald Reagan sent a pile of suggestions to Nicholas Meyer how it should be edited.

The scenes of Air Force personnel aboard the Airborne Command Post, in the command center receiving news of the incoming attack, the B-52 crew, and the crew in the silo launching their missiles, are footage of actual military personnel during a drill, and had been aired in a CBS documentary, First Strike (1979). In the original footage, the silo is "destroyed" by an incoming "attack" just moments before launching its missiles, which is why the final seconds of the launch countdown are not seen in this movie.

Three other directors turned down the chance to helm the film before Nicholas Meyer accepted.

The Soviet ambassador is named Anatoli Kuragin, the name of a character from Leo Tolstoy's "War and Peace".

During the attack sequence, there are several cuts of footage acquired during the U.S. atomic testing that took place in the 1950s. The nuclear yield on these tests ranged from fifteen to forty-seven kilotons. In the early 1980s, the Soviet Union had deployed ICBM forces with multiple warheads that carried hydrogen weapons with a yield between one thousand and five thousand kilotons (one to five megatons).

Some of the scenes were shot on-location in Kansas City, Missouri. During the opening credits, the Kansas City Stockyards, the Truman Sports Complex (with the Chiefs and Royals Stadiums), the Liberty Memorial Monument, the downtown area, and the Country Club Plaza and surrounding neighborhoods and parks can be seen. Scenes of Jason Robards, Jr. and his daughter talking near the Liberty Memorial, glancing over Crown Center, location shots at the Kansas City Board of Trade, and houses in the Brookside neighborhood can all be seen in the film prior to the attack. Hundreds of people can also be seen crowding into a fallout shelter in the basement of the old Fidelity National Bank in downtown Kansas City, just before the bombs hit. At the end of the film, Jason Robards, Jr. can be seen walking through the rubble of the old St. Joseph Hospital, which was being demolished at the time.

When production began, the nuclear attack sequence was supposed to be done with miniatures and models instead of stock footage, but budget and time constraints forced the producers to use the latter.

Although David Raksin and Virgil Thomson are credited with composing the soundtrack, only Raksin wrote a complete original score for the film. Nicholas Meyer removed much of the Raksin score and inserted cues Thomson had written for the documentary The River (1938) and gave Thomson partial scoring credit.

This was the next project for Nicholas Meyer and Bibi Besch after completing Star Trek II: The Wrath of Khan (1982).

Jason Robards, Jr. appeared in another post-apocalyptic science fiction film, A Boy and His Dog (1975).

The idea for the title came from Stu Samuels, who was ABC's Executive Vice President of television movies and miniseries. He wanted it to convey that this was the story of the fallout, not the nuclear war itself.

The Americans (2013), season four, episode nine, "The Day After", depicted the spy family watching this movie with their F.B.I. neighbors.

When the missle is launched from the silo next to the Hendry farm, a white horse is shown running in slow motion. This symbolizes the first of the Four Horsemen of the Apocalypse as described in Revelation 6:1-2 ('...and behold, a white horse...').

The film was part of a 1980s cycle of films about atomic bombs and nuclear warfare which started in 1979 with The China Syndrome (1979). The films included Silkwood (1983), Testament (1983), Threads (1984), WarGames (1983), The Day After (1983), The Atomic Cafe (1982), The Manhattan Project (1986), Whoops Apocalypse (1982), Special Bulletin (1983), Ground Zero (1987), Hadashi no Gen (1983), Rules of Engagement (1989), When the Wind Blows (1986), Pisma myortvogo cheloveka (1986), Memoirs of a Survivor (1981), The Chain Reaction (1980), and Miracle Mile (1988).

The nuclear missile launch code, sent to the Minuteman silos to fire their missiles at the Soviet Union, was portrayed in the film as "Alpha-7-8-November-Foxtrot-1-5-2-2" with an authentication of "Delta X-ray".

The opening credits featured an updated version of the selection "The Old South" from "The River" by Virgil Thomson. The closing credits featured an updated instrumental of the hymn "How Firm a Foundation", which itself inspired some of Thomson's work, notably "The River".

The special effects company listed in the end credits is Praxis Filmworks. Praxis is the name given to the Klingon moon that explodes in Star Trek VI: The Undiscovered Country (1991) directed by Nicholas Meyer.

The movie was released theatrically in France in 1984.

In the original telecast, the ending disclaimer had a paragraph that been omitted from all home video version of the film: "In it's [sic] presentation ABC has taken no position as to how such an event can be initiated or avoided."

Arthur Ashe: A television news reader during the scene in which the University of Kansas students are discussing the developing crisis during enrollment. Ashe died of A.I.D.S. complications in 1993. He contracted the disease from a blood transfusion during open heart surgery he had around the time of this film.

In the original script, Nurse Nancy Bauer (JoBeth Williams), who asked whether the living really did envy the dead, died on-camera. The scene was cut, and Bower died off-camera. One of the doctors said she died of meningitis. However, the sound was so garbled in the first viewing, that many viewers couldn't hear the cause of death at all.