The film was in development since 1990 at Universal Pictures, 20th Century Fox, and New Line Cinema, before Marvel Studios reacquired the rights in 2006. Marvel put the project in production as its first self-financed film, with Paramount Pictures as its distributor. Favreau signed on as director, aiming for a naturalistic feel, and he chose to shoot the film primarily in California, rejecting the East Coast setting of the comics to differentiate the film from numerous superhero films set in New York City-esque environments. During filming, the actors were free to create their own dialogue because pre-production was focused on the story and action. Rubber and metal versions of the armors, created by Stan Winston's company, were mixed with computer-generated imagery to create the title character. Hasbro and Sega sold merchandise, and product placement deals were made with Audi, Burger King, LG and 7-Eleven.

Reviews were positive, particularly praising Downey's performance. The American Film Institute selected the film as one of the ten best of the year. Downey, Favreau, and Paltrow returned for the sequel Iron Man 2, released on May 7, 2010. Downey made a cameo appearance as Stark in The Incredible Hulk and starred as the character again in the 2012 crossover film The Avengers. Downey will reprise the role for a fifth time in another sequel, Iron Man 3, which is set for release on May 3, 2013.

Plot
Playboy and genius Tony Stark, who has inherited the defense contractor Stark Industries from his father, is in war-torn Afghanistan with his friend and military liaison, Lieutenant Colonel James Rhodes to demonstrate the new "Jericho" missile. Stark is critically wounded in an ambush and imprisoned in a cave by the terrorist group the Ten Rings. An electromagnet grafted into Stark's chest by fellow captive Yinsen keeps the shrapnel that wounded him from reaching his heart and killing him. Ten Rings leader Raza offers Stark freedom in exchange for building a Jericho missile for the group, but Tony and Yinsen agree Raza will not keep his word.

Stark and Yinsen secretly build a powerful electric generator called an arc reactor, to power Stark's electromagnet, and then begin to build a suit of armor which is later named "Mark I" to escape. The Ten Rings attack the workshop when they discover that Stark was trying to escape. Yinsen sacrifices himself to divert them while Stark's suit powers up. The armored Stark battles his way out of the cave to find the dying Yinsen, then an enraged Stark burns the Ten Rings weapons and flies away, only to crash in the desert, destroying the suit. After being rescued by Rhodes, Stark returns home and announces that his company will no longer manufacture weapons. Obadiah Stane, his father's old partner and the company's manager, advises Stark that this may ruin Stark Industries and his father's legacy and asked to see what Stark has been working on in his home workshop. In his home workshop, Stark builds an improved version of his suit, as well as a more powerful arc reactor for his chest.

At Stark's first public appearance after his return, a charity event that is put on by Stark's company, reporter Christine Everhart informs him that Stark Industries weapons, including the Jericho, were recently delivered to the Ten Rings and are being used to attack Yinsen's home village, Gulmira. Stark also learns that Stane is trying to replace him as head of the company. Enraged, Stark dons his new armor and flies to Afghanistan, where he saves Yinsen's village and delivers a devastating blow to the Ten Rings. While flying home, Stark is shot at by two F-22 Raptor fighter jets. He phones Rhodes and reveals his secret identity in an attempt to end the attack. Meanwhile, the Ten Rings gather the pieces of Stark's prototype suit and meet with Stane, who subdues Raza with a sonic device and has the rest of the group eliminated. He has a new suit reverse engineered from the wreckage. Seeking to find any other weapons delivered to the Ten Rings, Stark sends assistant Virginia "Pepper" Potts to hack into the company computer system from Stane's office. She discovers Stane has been supplying the terrorists and hired the Ten Rings to kill Stark, but the group reneged. Potts later meets with Agent Phil Coulson of the "Strategic Homeland Intervention, Enforcement and Logistics Division", a counter-terrorism agency, to inform him of Stane's activities.

Stane's scientists cannot duplicate Stark's arc reactor so Stane ambushes Stark at home, using his sonic device to paralyze him, and takes his arc reactor. Left to die, Stark manages to crawl to his lab and plug in his original reactor. Potts and several S.H.I.E.L.D. agents attempt to arrest Stane, but he dons his suit and attacks them. Stark fights Stane, but is overmatched without his new reactor to run his suit at full capacity. Stark lures Stane atop the Stark Industries building and instructs Potts to overload the large arc reactor there. This unleashes a massive electrical surge that knocks Stane unconscious, causing him and his armor to fall into the exploding reactor, killing him.

The next day, the press has dubbed the armored hero "Iron Man". Agent Coulson gives Stark a cover story to explain the events of the night and Stane's death. At a press conference, Stark begins giving the cover story, but then announces that he is Iron Man, prompting the reporters to swarm the stage and ask more questions.

In a post-credits scene, S.H.I.E.L.D. Director Nick Fury visits Stark at home, and, noting that Iron Man is not "the only superhero in the world", says he wants to discuss the "Avengers Initiative".

Filming
Production was based in the former Hughes Company soundstages in Playa Vista, Los Angeles, California. Favreau rejected the East Coast setting of the comic books because many superhero films had already been set there. Howard Hughes was one of the inspirations for the comic book, and the filmmakers acknowledged the coincidence that they would film Iron Man creating the flying Mark III where the Hughes H-4 Hercules was built.

Filming began on March 12, 2007, with the first few weeks spent on Stark's captivity in Afghanistan. The cave where Stark is imprisoned was a 150- to 200-yard (150–200 m) long set, which had movable forks in the caverns to allow greater freedom for the film's crew. Production designer J. Michael Riva saw footage of a Taliban fighter in Afghanistan, and saw the cold breath as he spoke: realizing remote caves are actually very cold, Riva placed an air conditioning system in the set. He also sought Downey's advice about makeshift objects in prison, such as a sock being used to make tea. Afterwards, Stark's capture was filmed at Lone Pine, and other exterior scenes in Afghanistan were filmed at Olancha Sand Dunes, where the crew endured two days of 40 to 60 mile per hour (60 to 100 km/h) winds.

Filming at Edwards Air Force Base began in mid-April, and wrapped on May 2. Exterior shots of Stark's home were digitally composited on footage of Point Dume in Malibu, while the interior was built at Playa Vista, where Favreau and Riva aimed to make Stark's home look less futuristic and more "grease monkey". Filming concluded on June 25, 2007 at Caesars Palace in Las Vegas, Nevada. Favreau, a newcomer to action films, remarked, "I'm shocked that I  on schedule. I thought that there were going to be many curveballs". He hired "people who are good at creating action", so "the human story  like it belongs to the comic book genre".

There was much improvisation in dialogue scenes, because the script was not completed when filming began (the filmmakers had focused on the story making sense and planning the action). Favreau acknowledged that improvisation would make the film feel more natural. Some scenes were shot with two cameras to capture lines said on the spot. Multiple takes were done, as Downey wanted to try something new each time. It was Downey's idea to have Stark hold a news conference on the floor, and he created the speech Stark makes when demonstrating the Jericho weapon.

Brian Michael Bendis wrote three pages of dialogue for the Nick Fury cameo scene, with the filmmakers choosing the best lines for filming. The cameo was filmed with a skeleton crew in order to keep it a secret, but rumors appeared on the Internet only days later. Marvel Studios's Kevin Feige subsequently ordered the scene removed from all preview prints in order to maintain the surprise and keep fans guessing.

Effects
Favreau wanted the film to be believable by showing the construction of the suit in its three stages. Stan Winston, a fan of the comic book, and his company built metal and rubber versions of the armors. They had previously worked on Favreau's Zathura. Favreau's main concern with the effects was whether the transition between the computer-generated and practical costumes would be too obvious. Industrial Light & Magic (ILM) was hired to create the bulk of the visual effects with additional work being completed by The Orphanage and The Embassy; Favreau trusted ILM after seeing Pirates of the Caribbean: At World's End and Transformers.

The Mark I design was intended to look like it was built from spare parts: particularly, the back is less armored than the front, as Stark would use his resources to make a forward attack. It also foreshadows the design of Stane's armor. A single 90-pound (41 kg) version was built, causing concern when a stuntman fell over inside it. Both the stuntman and the suit were unscathed. The armor was also designed to only have its top half worn at times. The Embassy created a digital version of the Mark I. Stan Winston Studios built a 10-foot (3.0 m), 800-pound (360 kg) animatronic version of the comic character "Iron Monger" (Obadiah Stane), a name which Obadiah Stane calls Tony Stark and himself earlier in the film as a reference, but is never actually used for the suit itself. The animatronic required five operators for the arm, and was built on a gimbal to simulate walking. A scale model was used for the shots of it being built.

The Mark II resembles an airplane prototype, with visible flaps. Iron Man comic book artist Adi Granov designed the Mark III with illustrator Phil Saunders. Granov's designs were the primary inspiration for the film's design, and he came on board the film after he recognized his work on Jon Favreau's MySpace page. Saunders streamlined Granov's concept art, making it stealthier and less cartoonish in its proportions. Sometimes, Downey would only wear the helmet, sleeves and chest of the costume over a motion capture suit. For shots of the Mark III flying, it was animated to look realistic by taking off slowly, and landing quickly. To generate shots of Iron Man and the F-22 Raptors battling, cameras were flown in the air to provide reference for physics, wind and frost on the lenses. For further study of the physics of flying, skydivers were filmed in a vertical wind tunnel.

Phil Saunders created concept art for the War Machine armor and said that it was originally intended to be used in the film but was "cut from the script about halfway through pre-production." Saunders said that the War Machine armor "was going to be called the Mark IV armor and would have had weaponized swap-out parts that would be worn over the original Mark III armor," and that it "would have been worn by Tony Stark in the final battle sequence."

Release
The premiere was held at the Greater Union theater at George Street, Sydney, on April 14, 2008. The film was released worldwide except for Japan between April 30 and May 7, 2008, with Japan to receive the film in September 2008.

Critical reception
Iron Man received positive reviews from film critics. On May 1, 2008, the film was identified as the "best-reviewed film of the year so far" by Jen Yamato of review aggregator Rotten Tomatoes, with the site reporting at that time the film had received a rating of 95% based on 107 reviews and this rating has held its place as of January 2010. The film currently holds a score of 93% based on 241 reviews. Metacritic gave the film normalized average score of 79%, based on 38 reviews.

Among the major trade journals, Todd McCarthy in Variety called the film an "expansively entertaining special effects extravaganza" with "fresh energy and stylistic polish", while Kirk Honeycutt of The Hollywood Reporter praised the film while nonetheless finding "disappointment  a climatic  battle between different Iron Man prototypes  how did Tony's nemesis learn how to use the suit?" In one of the first major-daily newspaper reviews, Frank Lovece of Newsday lauded the film's "emotional truth  pitch-perfect casting and plausibly rendered super-science" that made it "faithful to the source material while updating it – and recognizing what's made that material so enduring isn't just the high-tech cool of a man in a metal suit, but the human condition that got him there". A. O. Scott of The New York Times called the film "an unusually good superhero picture. Or at least – since it certainly has its problems – a superhero movie that's good in unusual ways."

Among the specialty press, Garth Franklin of Dark Horizons commended the "impressive sets and mechanics that combine smoothly with relatively seamless CG", and said, "Robert Downey Jr., along with director Jon Favreau  help this rise above formula. The result is something that, whilst hardly original or groundbreaking, is nevertheless refreshing in its earnestness to avoid dark dramatic stylings in favor of an easy-going, crowd-pleasing action movie with a sprinkle of anti-war and redemption themes". IGN's Todd Gilchrist recognized Downey as "the best thing" in a film that "functions on autopilot, providing requisite story developments and character details to fill in this default 'origin story' while the actors successfully breathe life into their otherwise conventional roles".

Among major metropolitan weeklies, David Edelstein of New York magazine called the film "a shapely piece of mythmaking  Favreau doesn't go in for stylized comic-book frames, at least in the first half. He gets real with it – you'd think you were watching a military thriller", while conversely, David Denby of The New Yorker put forth a negative review, claiming "a slightly depressed, going-through-the-motions feel to the entire show  Gwyneth Paltrow, widening her eyes and palpitating, can't do much with an antique role as Stark's girl Friday, who loves him but can't say so; Terrence Howard, playing a military man who chases around after Stark, looks dispirited and taken for granted". Looking at the sociocultural aspects of the film, Cristobal Giraldez Catalan at Bright Lights Film Journal argues that, "Iron Man is far more than playboy fantasy; it is American foreign policy realized without context....Iron Man, with narrative and directorial precision, once again provides the high-fidelity misogyny and anti-Muslim rhetoric Hollywood is known for."

In a poll by the website Rotten Tomatoes in 2010, Iron Man was ranked among the best films of its genre, losing only to Persepolis.

Roger Ebert and Richard Corliss named Iron Man as among their favorite films of 2008.

Box office
In its opening weekend, Iron Man grossed $98,618,668 in 4,105 theaters in the United States and Canada, ranking #1 at the box office, giving it the eleventh biggest-opening weekend, ninth-widest release in terms of theaters, and the third highest-grossing opening weekend of 2008 behind Indiana Jones and the Kingdom of the Crystal Skull and The Dark Knight. It grossed $35.2 million on its first day, giving it the thirteenth biggest-opening day. Iron Man had the second-best premiere for a non-sequel, behind Spider-Man. It had the fourth biggest-opening for a superhero film. Iron Man was also the #1 film in the U.S. and Canada in its second weekend, grossing $51.1 million, giving it the twelfth-best second weekend and the fifth-best for a non-sequel. On June 18, 2008, Iron Man became that year's first film to pass the $300 million mark for the domestic box office. As of July 2009, Iron Man has grossed $585,174,222 worldwide, $318,412,101 in the U.S. and Canada and $266,762,121 in other territories.

Awards
Iron Man was selected by the American Film Institute as one of the ten best films of the year. The film was nominated for the Academy Awards for Best Visual Effects and Best Sound Editing at the 81st Academy Awards, but lost to another Paramount film The Curious Case of Benjamin Button and The Dark Knight, respectively. It was nominated for nine Saturn Awards, winning Best Science Fiction Film, Best Director for Favreau and Best Actor for Downey. In 2008, Iron Man was selected by Empire magazine as one of The 500 Greatest Movies of All Time. Tony Stark was also selected as one of The 100 Greatest Movie Characters of All Time. On their list of the 100 Greatest Fictional Characters, Fandomania.com ranked Iron Man at number 37.

It was nominated for Favorite Movie at the 2009 Kids' Choice Awards but lost to High School Musical 3: Senior Year.