In season four, episode five, "Day 4: 11:00 a.m. - 12:00 p.m.", Debbie's cell phone rang with a valid California phone number on the caller ID. Many fans noticed this and called the number, Some callers heard a voice mail message telling them that they called the 24 prop phone and to leave a message. Others spoke with various people, including Production Designer Joseph A. Hodges and stars Kim Raver (Audrey Raines) and Carlos Bernard (Tony Almeida). Hodges later stated in an interview that Director Jon Cassar came up with the idea for the "Fan Phone" because the two of them often got bored scouting new shooting locations and wanted a chance to interact with the audience. Hodges indicated they received around eighty thousand calls on the line in the first week. There was also a valid California cell phone number in season three, episode three, "Day 3: 3 p.m. - 4 p.m.", Chase's cell number appeared on Jack's cell.
Partway through season two, Kiefer Sutherland injured his leg while exiting his trailer, so a small scene was written where Jack Bauer must pull a piece of shrapnel from his leg after a plane crash to explain Sutherland's limp.
In season three, it's revealed that Jack received an intricate tattoo on the inside of his left forearm as part of his previous deep-cover operation with the Salazar brothers. Instead of spending several hours in the make-up chair on days when the tattoo needed to be shown, Kiefer Sutherland opted instead simply to get the actual tattoo.
Jack was only an official C.T.U. employee for three of the eight seasons; in season one as the C.T.U. Director, in season two his credentials are reinstated after being "inactive" for eighteen months, and in season three as Director of Field Ops. During each of the other seasons, he was "contracted" as a freelance and given temporary clearance; in season four he asked Erin Driscoll to reinstate him on a provisional basis. (With the exception of season seven, as C.T.U. had been disbanded.)
During season two shooting, Elisha Cuthbert was bitten by the mountain lion who menaced her in one of the plotlines. Before shooting the scene the animal trainer suggested she "meet" the mountain lion before shooting, when she went to pet the mountain lion it bit her hand. She was taken to the hospital, treated for puncture wounds and was given a tetanus shot.
Gabriel Macht was originally offered the role of Jack's partner Chase Edmunds, but the producers were so impressed by James Badge Dale's audition, they offered him the role and promised Gabriel Macht a significant role in the next season. This never materialized.
In season three, whenever Jack goes into the holding facility which houses Salazar, at some point, he is picked up by security cameras. The legend on the video surveillance monitor at the guards' station shows constantly that he is being taped by camera #24.
"24" broke with longstanding convention in television regarding the filming of telephone conversations. Ordinarily, when a telephone conversation is shot, only the actor or actress whose end is being shot that day is actually present, with the other character's lines read by a Script Supervisor to maintain appropriate timing. But since telephone conversations are so frequent and so vital to the show, the show instead, whenever feasible, had both performers be present for the shooting of a telephone conversation, even though obviously only one was being shot at the time. An example of this technique is available on the season 2 DVD set, as Penny Johnson Jerald is present to provide her lines in a phone conversation with Dennis Haysbert, who was actually being filmed at the time. Leslie Hope has commented that while she shared relatively little actual screentime with Kiefer Sutherland, she nonetheless felt she had had a rewarding acting experience with him, due to him being present for their many phone call scenes.
Seasons one and three were the only ones where no changes to the main cast (e.g. guest stars being upgraded to regular status) occurred during the season. They were also the only two seasons in which each main cast member appeared in every episode of the season.
In seasons one and six, there is a C.T.U. character called Milo Pressman (played by Eric Balfour). There was a character called Milo Pressman, who ran a scrapyard in the Stephen King's story "The Body" in his book "Different Seasons". The story was later made into Stand by Me (1986) in which Kiefer Sutherland starred.
In preparation for season seven of this series, the executive producers and staff writers strongly considered moving the action of the story from Los Angeles to New York City. They felt that Los Angeles had been the target of terrorist attacks too many times in the previous six seasons, and that the location of the drama needed an update. They debated whether to place season seven in New York City or Washington, D.C., and ultimately decided on the District of Columbia. They reasoned that, because the majority of principal photography would still film in Los Angeles, that it would be easier to fake Washington, D.C. using Los Angeles locations, than to try to effectively fake New York City. The production made three trips to Washington, D.C. before the WGA strike in November 2007, the other Washington, D.C. shots were inserted during post-production using greenscreens.
Jayne Atkinson originally auditioned for the role of the President's wife, Martha Logan, in season five. Jean Smart was eventually cast as Mrs. Logan, and Atkinson was later cast in the role of C.T.U. Executive Karen Hayes. In a subsequent interview, Atkinson said that her audition for the role of Martha Logan had gone well, but that Jean Smart was perfect for the part. In addition, she felt a stronger connection to her role as Karen Hayes.
Each episode is supposed to take one hour of real time, but in actuality, due to commercial breaks three minutes are gradually added to the timer during the show in the breaks. The last three minutes of air time are used for viewing commercials, station identification, and scenes from the next episode. Each episode general runs for around forty-three minutes without commercials (slightly less in PAL territories).
In season five, the relationship between President Logan and Christopher Henderson mirrored Jack's relationship with President Palmer; the Operative and the Politician working together to do what they felt was best for their country. Henderson and Logan were the polar opposite from Jack and Palmer as far as methods and intentions.
With the exception of President Daniels and Priesident Keeler, each of the United States Presidents that were married, ended up divorcing their spouses. (David Palmer divorced his wife before he took office. Daniels was a widower and neither he nor Palmer ever had a First Lady. Whether or not Keeler had a wife was never mentioned.)
The season six plotline involving hostiles taking over C.T.U. headquarters and Jack's nephew eluding them by crawling through air ducts almost exactly parallels a plotline from 24: The Game (2006), except that in the game it was Jack's daughter Kim eluding the terrorists.
In season three, Stephen Saunders demands that the President reveal some classified information, which would then be sent to him via a website. The website he mentioned is SylviaImports.com. This site was actually registered by Rodney Charters, the show's Director of Photography (and director of a couple of second season episodes). It contained the following text message: "A Big Thank-you from the crew of 24 (2001). Thanks for watching, we love making it for you, and yes, we did get picked up for season four."
Jack Bauer has a Bachelor's Degree in English Literature from UCLA and a Master's Degree in Criminology and Law from UC Berkeley. Kim Bauer has an Associate's Degree in Computer Programming from Santa Monica College. President Palmer has a Bachelor's Degree in Political Economy from Georgetown University, and a Juris Doctorate from the University of Maryland School of Law. Tony Almeida has a Bachelor's Degree in Engineering and Computer Science from San Diego State University and a Master's Degree in Computer Science from Stanford University. Michelle Dessler has a Bachelor's Degree in Computer Science from UC Davis. Sherry Palmer has a Bachelor's Degree in Sociology from Georgetown University.
Season six shared many plot elements with the video game Call of Duty 4: Modern Warfare (2007). Both plots involve a one-armed, ultra-nationalist Russian selling nuclear bombs to a Middle Eastern faction. Both plots involve detonating a nuclear bomb with the ultra-nationalist wanting the Middle Eastern faction to take the blame. Both feature characters named Al-Assad (Al-Asad in Call of Duty).
In season three, a Mexican airplane appears briefly during Salazar and Bauer's landing on Mexican ground. The logo on its side reads "Aeromexicana". The name is comprised of Mexico's two largest airlines "Aeromexico" and "Mexicana".
Reiko Aylesworth originally auditioned for the role of Nina Myers, as well as the role of Kate Warner in season two. The character she landed Michelle Dessler, ended up with. Much more important role in the series than both of the other characters she auditioned for.
Omid Abtahi is one of three actors to return to 24 as a another character. He's "Safa" in 24: Day 4: 7:00 p.m.-8:00 p.m. (2005), and "Jibraan Al-Zarian" in 24: Day 7: 3:00 a.m.-4:00 a.m. (2009). Tony Todd played Detective Norris during Day 3 and General Juma in Redemption and Day 7. In addition, actor Anthony Azizi played Mamud Faheen in Season 2 and then played Rafique, a henchman of Marwan, in season 4.
The show became so popular with college students, it was rumored a drinking game was created, whenever Sutherland spoke Bauer's trademark words "damn it", participants would take turns binge drinking alcohol until the episode ended.
Jack's last name came from a character we've seen in La Femme Nikita (1997) (Peter Bauer, #1.06). The famous split screen we see on twenty-four was used on La Femme Nikita #1.03 and Jack's motto "whatever it takes" is said by Michael and Madeleine in the first season of La Femme Nikita.
When the series was continued after the success of the first season, there were plans to abandon the real-time format, and resume with more conventional episode formats (i.e. cutting out time periods and making episodes more stand-alone). However, several series prominents, including main star Kiefer Sutherland, successfully pleaded to keep the real-time format.
Harris Yulin, who played the recurring character of N.S.A. Director Roger Stantonv in season two, is not credited at all in the opening or ending credits. All recurring and guest stars have to share their credits on--screen with one or two other actors, but Yulin wanted to appear alone on them. Because this was not possible, he decided not to be credited at all.
After the show had become wildly popular, a tag line in reference to the main character circulated among viewers; "How many lives does Jack have?" (Stemming from the extreme circumstances that Jack faced each day.) In Speed (1994), Joe Morton's character Lt. McMahon asked the same question of the main character Jack Traven.
During the shoot for season four, a special six-minute segment was shot for the U.S. version of the season three DVD where Jack loses his job at C.T.U., an antagonist of season four arrives in the U.S., and Jack has an intimate moment with his new girlfriend. This did not appear on any of the other versions of the DVD released earlier in the summer, however, it does appear on the UK and German DVD release. An extended version of this segment (as stated in the commentary by Director Jon Cassar) is available on the UK DVD release of season four.
For season four, Writer and Executive Producer Evan Katz was such a huge fan of Australian music duo Grant McLennan and Robert Forster of the band The Go-Betweens, that he named the sinister corporation McLennan-Forster after them.
Paul Blackthorne, who played season three main villain, Saunders, originally auditioned for the role of Amador, another one of the season three villains. After failing the audition, his agent negotiated with the producers and managed to get the role of Saunders.
The character name Alberta Green (Tamara Tunie) was named after the late actress Alberta Watson, who was originally going to play the part. Watson later went on to play C.T.U. Director Erin Driscoll in season four.
Six main actors from RoboCop (1987) have been cast as main characters throughout the series. They include: Peter Weller: played Officer Alex J. Murphy in Robocop and Christopher Henderson on this show. Kurtwood Smith: played Clarence Boddicker in Robocop and Senator Blaine Mayer on this show. Ray Wise: played Leon Nash in Robocop and Vice President Hal Gardner on this show. Paul McCrane played Emil Antonowsky in Robocop and Graem on this show. Jesse D. Goins played Joe Cox in Robocop and Alan Hayes on this show. Edward Edwards played Manson in Robocop and Colonel Lamb on this show.
Cherry Jones told Newsweek Magazine that her models for her characterization of President Allison Taylor are Eleanor Roosevelt, Golda Meir, and John Wayne. Cherry Jones also portrayed Eleanor Roosevelt in Amelia (2009).
According to a behind-the-scenes disc included in the series DVD box set. Carlos Bernard's character, Tony Almeida's, first name was originally going to be "Antonio". However, Kiefer Sutherland had a hard time pronouncing "Antonio", so the character's name was changed to "Tony".
No references to the terrorist attacks of 9/11 were made during the first season, as they had happened only a few months before. In contrast, season two clearly referenced the national trauma and consequences that 9/11 had caused.
In season four, while Mandy (Mia Kirshner) has Tony Almeida (Carlos Bernard) held hostage, she goes to her neighbors' apartment and one of them calls her "Rothenberg" This is the same last name as C.T.U. Agent Shari Rothenberg (Kate Mara) in season five.
At the power plant before Palmer's breakfast speech, Jack runs into old friend and Palmer staffer, Jessica Abrams. In conversation, she refers to mutual old friend Tracy Zigler, who had erroneously reported that Jack and Teri had divorced. Both characters were named after members of the production crew; Jessica Abrams was the Script Coordinator, and Tracy Zigler was the Script Supervisor.
In the Day 5 episode 4:00 p.m.-5:00 p.m. Audrey identifies herself to the secretary as Jane Espenson. Jane Espenson is a writer who had previously worked with David Fury (one of this show's producers) on several Joss Whedon shows.
Senator John McCain appeared in season five, episode seven, "Day 5: 1 p.m. - 2 p.m.", albeit half way through the episode. He brought Audrey Raines' character an informational folder. He appears in the top left split screen at the 1:34 mark just after the commercial break.
According to Kiefer Sutherland, Nina Myers was a loyal C.T.U. Agent in the script, but the character was changed into a villain by the writers after they had already filmed episodes of "good Nina". She was also supposed to be dead when Jack shoots her on the side of the road, and again the decision was made after they had shot the scene.
In season one, the main villains the Drazen family were comprised of a father and two sons. The father and the younger son (Dennis Hopper and Misha Collins) were portrayed by two American actors who spoke with Russian accents, while the older son (Zeljko Ivanek) was portrayed by a Slovenian actor who spoke with an American accent.
In the second half of season six, Wayne Palmer collapsed and the show never officially stated whether he survived the attack on his life. But when 24: Redemption (2008) aired, there was a fan who noticed a very small and very well hidden detail: The President in 24: Redemption is Noah Daniels, who took over as President after Wayne Palmer was unfit to continue as President. In a scene where Noah Daniels is in the Oval Office, he's holding a newspaper. The fan zoomed in on a paragraph of the paper, where there was mention "of the death of the former President in office." This was commented on by one of the Executive Producers, who confirmed the death of Wayne Palmer, but also admitted that he would rather have had Wayne Palmers death be addressed in a more informative way. After the airing of 24: Redemption (2008), actor D.B. Woodside was interviewed about his characters apparent death, to which Woodside said he had no idea about even before the airing of the movie.