To date Agent Coulson's origins have yet to be revealed. However, as he holds a position of command within S.H.I.E.L.D. thus we can assume that he has had some sort of military experience before joining.
Agent Coulson was created specifically for the 2008 live action motion picture, Iron Man. He had not made an actual comic book appearance until the release of an exclusive webcomic in April 2010, namely the digital comic "Iron Man 2: Phil Coulson: Agent of S.H.I.E.L.D. #1", later printed in actual comic-format. Although this is his first comicbook appearance, it would take another year for Agent Coulson to be established in the main Marvel universe. He first appeared (as "Cheese") in the 616 Main Marvel universe in Battle Scars Issue 1 (2011). It was only revealed in issue 6 of that series that "Cheese" was in fact Phil Coulson.
Mayor Story Arcs
Agent Coulson, as "Cheese", was a fellow Army Ranger and teammate of Marcus Johnson. He assisted Marcus as he was pursued by Taskmaster, Deadpool, Captain America, and Orion for unknown reasons. During these events, Marcus knocked out Coulson and left him behind to protect him. While separated, Marcus discovered that he was the son of Nick Fury. At this point Coulson contacted Captain America. Coulson's goal was to save his friend's life by enlisting Captain America, The Avengers, and SHIELD. The end of the series depicts Marcus, being called Nick Fury Jr., and Coulson joining S.H.I.E.L.D. and reporting to Director Daisy Johnson.
Phil Coulson and Nick Fury Jr. have been tasked to put together a new team of Avengers for secret covert operations. He firstly asks Hawkeye and Black Widow to join the team.
Digital comic: Iron Man 2: Phil Coulson
Agent Coulson's very first appearance outside the movies was in Iron Man 2: Phil Coulson: Agent of S.H.I.E.L.D. #1, witch build on the Iron Man 2 movie and is part of the 'movie universe'. It took another year or so before agent Coulson would appear in the regular Marvel Universe.
Actor Clark Gregg has portrayed Agent Coulson in all 4 of his cinematic appearances to date.
When Agent Coulson appeared in the first Iron Man film, he was repeatedly ignored by both Tony Stark and Pepper Potts. Agent Coulson was meant to debrief Stark after escaping his kidnappers in Afghanistan, however his introduction was overly lengthy as he announced that he was from the Strategic Homeland Intervention, Enforcement and Logistics Division. He was a source of humour; providing a running joke throughout the film, which lead to the final revelation of the acronym " S.H.I.E.L.D.".
It wasn't until the movie was nearing it's climax that his character took a more serious turn. When Pepper Potts had taken secret files from Obadiah Stane's personal computer, she realized that he life was in danger. Therefore, the next time Agent Coulson approached her she latched on to him and insisted that he and his men accompany her immediately. Subsequently, Coulson led a team of men into the Stark facility where the Iron Monger armor had been created. Agent Coulson clearly demonstrated his training as he lead his team silently through the premises and used weapons technology to break into secure areas.
Iron Man 2
His appearances in the sequel movie, Iron Man 2, were more limited. Agent Coulson didn't appear until after Iron Man had been in a drunken brawl with War Machine. Coulson aided Nick Fury in explaining the terms of Stark's House Arrest. Soon after, he announced that he had been called away to a situation that was developing in New Mexico. It was clear that Agent Coulson was a figure of authority within S.H.I.E.L.D..
In the post-credits scene to Iron Man 2, Agent Coulson arrived at the top of a crater to see several trucks and people gathered around something unique. It was revealed to be Thor's powerful hammer, Mjolnir. It was the first hint at the Thor movie. The scene was repeated within the movie, therefore insinuating that the events of both movies took place at the same time.
In the Thor movie, Agent Coulson is shown as a figure not only of authority, but of unquestionable political power, too. He repossesses the technology and data recorded by Jane Foster, but remains cool at all times and even offers monetary compensation (although it only serves to infuriate her further). He has the presence of a politician, while acting like a mysterious 'Man In Black' who casually steals someone' life's work on semi-regular basis.
Later, he orchestrates the security surrounding the Mjolnir crash site. This is most evident when he calls Agent Barton into action, but commands his movements via walkie-talkie. Instead of giving the order for Barton to shoot Thor as he tears through the complex, Coulson let the God of Thunder make his way to Mjolnir. This results in the spirit crushing scene in which Thor (who is still 'not worthy' to wield Mjolnir) can not lift the hammer & emotionally breaks down. Coulson calmly analyses his opponent and later interrogates him, determined to learn where Thor was training in several different fighting techniques. The interrogation was unsuccessful, but it was the first time that a darker side to Agent Coulson's personality was seen.
When Erik Selvig appeared claiming that Thor was really Donald Blake MD, Coulson's men immediately detected the fake ID. However, it was ultimately Coulson's decision to release 'Donald Blake'. Whether it was so they could further observe Thor in a more natural environment, or because he took pity on them is currently unclear. The lighter side to Agent Coulson's personality is later restored as he comes to a tenuous agreement with Thor (after his immortal powers had been restored). Unintentionally, Coulson became the focus of a joke as Thor addresses him as "Son of Coul", based on the old Norse tradition the father's name as a son's surname.
Coulson also appears in the 2012 live action adaptation of the Avengers. During the movie it is shown Agent Coulson is a fan of Captain America, having a collection of Captain America trading cards. He was also present while Captain America was revived. After Loki breaks free on the Helicarrier, he tries to stop him with a blast gun but is back-stabbed by the god, and he apparently dies in Nick Fury's arms. It is hinted that Fury lied and that Agent Coulson is still alive somewhere.
Marvel's Agents of S.H.I.E.L.D
Phil Coulson returns from his apparent demise in the Avengers, in a show directed by the movie's director Joss Whedon.
Days after his death at the hands of Loki, Nick Fury ordered extreme measures to be taken to return Coulson to life. S.H.I.E.L.D. medical cut open his skull and by stimulating the sensors of the brain, the doctors were actually able to bring Coulson back. The process, however, was extremely, inhumanly agonizing for Coulson, who begged the doctors to let him die. In order to cope with that pain his memories were altered to believe he had recovered in Tahiti, after being "dead" for only eight seconds.
After his recovery, Coulson returned duty and assembled a small, highly trained team of agents including; black-ops specialist Grant Ward, ace pilot and weapons expert Melinda May, weapons engineer Leo Fitz, and bio-chemical researcher Jemma Simmons. Their base of operations is a large plane called the "Bus".
On their first mission the team investigated a man named Mike Peterson, who was able to survive an exploding building. Coulson and Ward abduct Skye, a Rising Tide hacktivist who had filmed a posted Mike exhibition of power, taking her back to the "Bus" for questioning. At first she refused to cooperate, but is eventually persuaded to share what she knows. The team discovers that Peterson had been supplied with a device by an unknown organization that granted him his powers. After visiting the site of the explosion, Coulson's team is able to recreate it and learn that it was caused by another subject exploding due to Extremis. While attempting to get info to the team, Skye is kidnapped by Peterson, now on the run, and makes her give him a clean slate. Coulson's team is able to track them down and subdue Peterson without him causing mass damage. With Peterson in S.H.I.E.L.D. custody, Coulson offers Skye a place on his team.
Soon after, the team is sent to Malta to rescue Dr. Franklin Hall, a S.H.I.E.L.D. asset and old teacher of teammates Fitz and Jemma. Coulson and Agent Ward infiltrated the compound of Ian Quinn to reach Hall, but found Hall unwilling to leave as he was determined to destroy the supply of Gravitonium procured by Quinn. In his attempt to destroy the supply, Hall was seemingly lost, enveloped by the Gravitonium. Believing that it was what Hall would have wanted, Coulson ordered the Gravitonium be stored at the Fridge in an unmarked vault.
Coulson became aware of a number of jewelry heists that he suspected were being committed by his old protégé, Akela Amador. Coulson and his team tracked her down and discovered that she was being controlled by an unknown handler through a bionic implant in her eye. They manage to subdue Amador, hijack the implant’s signal, and ultimately remove it. Coulson and May then track down Amador's handler, only for the man to drop dead from his own implant.
Next the team is assigned to retrieve Chan Ho Yin, a Hong Kong with pyrokinetic abilities, who had been abducted by a Centipede agent named Raina. They discover the Rising Tide leaked the information that led to his capture and the blame falls on Skye. She protests her innocence, claiming she knows another hacker who could have done. They head to Austin, Texas where Skye spends the night with the fellow Rising Tide hacker, Miles Lydon, warning him of S.H.I.E.L.D. Coulson and the rest of team arrive and arrest them both. They then fly back to Hong Kong and raid the Centipede facility, freeing Chan. Having grown mentally unstable Chan, now calling himself Scorch, attacked Coulson and May. Seeing no other option to subdue him non-lethally, Coulson ordered Agent May to inject him with a larger dose of Centipede, causing him to overload and detonate. Afterwards Miles is released from custody, now fitted with a tracking device that logs his computer activity. Skye is fitted with a similar device and permitted to remain on the team after she reveals that the reason joined the team and worked for Rising Tide was to find her missing parents, the only clues being a heavily redacted S.H.I.E.L.D. file. Coulson promises to help Skye find out what he could. True to his word, during a visit to the Hub, Coulson looked up the unredacted file. He told Skye the document was actually about an unidentified S.H.I.E.L.D. agent who dropped Skye off at the orphanage, choosing to keep the rest of the information secret until he knew more. To this end, he recruited Melinda May to help him.
Coulson soon began to question the circumstances of his recovery and have trouble with simple actions that should be performed through muscle memory. Also, he noticed every time Tahiti was mentioned, Coulson would automatically reply, "It's a magical place". Eventually he decided to investigate the matter himself and requested access to his "Death and Recovery" report, only to be told that he didn't have access to the file.
In order to counter the new Centipede super soldiers Phil recruits Mike Peterson to his team. The team traces Centipede to an abandoned factory, and walk into an ambush. Coulson's team discovers that the soldiers were subjected to the same eye implant to which Amador was subjected. Afterward Mike tells Coulson his thoughts about joining S.H.I.E.L.D full time, afraid to return to his son. Coulson assured him his son would think no different of him and told him to think on his decision. After a call to his son Mike informs the team that Centipede had abducted his son threatening to kill him if Peterson did not turn himself over. When Coulson escorts Peterson to the arranged prisoner exchange, Peterson reveals that Centipede really wants Coulson, not Peterson. After the exchange, Peterson tries to rescue Coulson, but Centipede sets off an explosion, apparently killing Peterson. After Raina escapes with Coulson, she tells him that he only needs to give Project Centipede the information regarding how he came back to life the day after he died.
Coulson is initially tortured by Edison Po, a Centipede operative, who tells him that their leader, the Clairvoyant, had been unable to sense Coulson since his resurrection. The Clairvoyant unsatisfied with Po’s methods kills him and has Raina continue the interrogation. Using a device that stimulates memory recovery, she helps Coulson to remember the horrific, catastrophic pain that he endured in the process of bringing him back and the bizarre machine that worked on his exposed brain. Fortunately Coulson’s team arrives before he could reveal any of this to Raina. Back aboard the "Bus" Coulson removes Skye's tracking bracelet.
While the rest of his team is investigating an incident at the S.H.I.E.L.D. Academy, Coulson and May follow a lead on Skye’s parents tracking Richard Lumley, the only surviving agent file, to Mexico City. Lumley reveals to Coulson that S.H.I.E.L.D. had designated the infant Skye as an 0-8-4, an object of unknown origin, and that all the other agents involved in the case were systematically killed afterward. After returning to the plane Coulson received a call from Ian Quinn who taunts him saying, "The Clairvoyant says hello".
Following a led on the Clairvoyant, Coulson and the team board a train in Italy where a Cybertek security team is shipping an unknown package to Ian Quinn. The team splits into groups, with Coulson and Simmons posing as a father and daughter while Fitz and Skye work with Ward and May to track down the package. However, the Cybertek team catches on causing Coulson and Ward to jump off the train, which mysteriously disappears afterward. Meet back up with May at the "Bus" they find the train and Simmons, but Fitz and Skye are gone. They track the two to Quinn's compound and raid it. Quinn is arrested and they discover Skye near death. Simmons trying to help, but can only sustain her temporarily by placing her into a hyperbaric chamber.
Coulson and the team rush Skye to a S.H.I.E.L.D. medical facility to save her life. However, the doctors are only able to stabilize her, forcing Coulson to bring her to the same location where he was revived. The team is joined by Agents John Garrett and Antoine Triplett. Coulson and Garrett interrogate Quinn and learn that the Clairvoyant had him shoot Skye, so he could learn how Coulson came back from the dead. The team travel to the "Guest House" to recover a miracle drug called GH-325. Coulson, Ward, Garrett and Fitz enter the facility and eliminate the two guards there only to find the place rigged with explosives. Fitz is able to find the drug, while Coulson finds a room marked "T.A.H.I.T.I." Inside, Coulson finds more of the drug as well as its source; the upper half of a blue-skinned humanoid corpse. Everyone is able to get out before the facility implodes and the drug is administered to Skye, despite Coulson's reservations.
Coulson appears as the undercover principal of Peter Parker's high school in 'Ultimate Spider-Man.'
Powers & Abilities
As a human being, Agent Coulson doesn't have any super powers. However, his position of authority within S.H.I.E.L.D. gives him political power to repossess belongings, break into weapons manufacturing facilities and wield firearms in public places. In the first Iron Man movie it was hinted at that he already had experience in covering up mysterious deaths (by providing a cover story for Stane's death), which was also something that Erik Selvig was concerned about when he recalled S.H.I.E.L.D.'s involvement in the disappearance of Dr Banner.
Just like most agents of S.H.I.E.L.D., Coulson will had have undergone rigorous miliraty training, is adept with a firearms and remains calm under pressure.