This is one of two movies in which Kevin Kline plays both the President of the United States and the man impersonating the President. The next was in Wild Wild West (1999), in which he portrayed President Ulysses S. Grant and impostor Artemus Gordon.
United States Senator Alfonse D'amato was set to cameo as himself but then pulled out of the film following issues between the Senate and Warner Brothers over the content in Ice-T's album "Cop Killer". D'Amato later attempted to return to the film after Ice-T parted ways with Warner Brothers but director Ivan Reitman turned him down.
The House of Delegates Chamber in the State Capitol building in Richmond, VA doubled for the House Chamber of the U.S. Capitol in Washington, DC. While the movie was being filmed, many members of the Virginia House of Delegates and visitors to the Capitol that day were used as extras.
The president's full name in the movie is William Harrison Mitchell; William Henry Harrison was a real president elected in 1840 and the first president to die in office. The vice president in the movie is named Nance; John Nance Garner was Franklin D. Roosevelt's vice president for two terms, and once derided the job as not being "worth a pitcher of warm piss" (bowdlerized at the time and often misquoted as "spit").
The House chamber and the swearing in of the next president were both filmed at the Virginia state capitol in Richmond VA. This building was a national capitol for the Confederate States of America during the American Civil War 1861-1895.
Gary Ross said he was very unhappy with an early draft of the script he had written. Despite being late in delivering the script and short on money, he started over from scratch, and had to take out a second loan on his house to finance the next draft.
The White House scenes were shot in a movie studio as the crew couldn't film the actual inside of the White House. Not only that, but they also built the White House exteriors themselves. Once that's completed they decorated the hallways, painted the portraits from the actual location, etc.
When Bob Alexander (Frank Langella) holds his news conference attacking President Mitchell (Kevin Kline), he is shown entering a red-orange-bricked building which is, in fact, the Renwick Gallery, in Washington, D.C. The Renwick Gallery is part of the Smithsonian Institution, and has been a public building, since 1972, dedicated to American folk and craft arts. A press conference of the type Bob Alexander calls, therefore, would not have actually been held inside the Renwick, especially given the political nature of the press conference. The Renwick is a registered National Landmark building.
There's a shot of a network news camera with the same CCN logo as that of the Clamp Cable Network found in Gremlins 2. The scene is leading into the press conference towards the end 1 hour 11 minutes in.
Sometimes incorrectly regarded as a goof: the First Lady is wearing a red dress as she exits a limousine with the President but in the next shot is wearing a gray dress. This is not an oversight. The President's tie is also different and the view out the window of the dining room clearly shows that the second scene, with the gray dress, is at the White House. The scene as they exit the limousine is not at the White House. Though it would seem logical for these two scenes to be sequential, they appear to occur on different days in the storyline.
In the beginning of the movie, when Dave is substituting for Pres. Mitchell (because Mitchell left the event to sleep with one of his secretaries, Randi), Dave is seen leaving the Monroe Hotel. President Kennedy was strongly rumored to have been having an affair with the actress Marilyn Monroe, so that might have been a nod to such an affair.
When they are swearing Gary Nance as president, they refer to him as the 45th President of the United States. This means that Mitchell would be the 44th. In real life, Barack Obama was the 44th president and Donald Trump was the 45th.
Some tribute is paid to the earlier film Mr. Smith Goes to Washington (1939). In addition to a similar storyline, this film's protagonist is shown to pass out in front of government officials (Smith passed out before the senate, Kovac before Congress).