After saving the life of a man who just had an accident at a race track, Happy Hogan is offered a job by the same man who happens to be the billionaire playboy Tony Stark. Soon, Tony takes him on a tour of his research plant and introduces him to Pepper Potts, his secretary. Happy immediately finds Pepper attractive, but the feeling is far from mutual since she only has eyes for Stark. A week after Stark has fired Professor Shapanka, the plant is visited by Jack Frost and Happy is frozen while trying to protect his boss. He and Pepper are unfrozen after Iron Man has forced Jack Frost to surrender.
Tony Stark is forced to cancel his presence at an employees' dinner. Happy is surprised, and delighted, when Pepper calls to ask him to be her escort. However at the ball, Pepper is more than distant, and Happy prefers to believe that she is trying to make him jealous.
Happy saves Tony Stark's life again when he shoves him out of the way of a heavy piece of metal dropping on him in his lab.
During his absence, Tony Stark sends Happy on an inspection tour of his plants, much to his dismay. Then the poor chauffeur has to act as an executive until his boss returns but he fails miserably.
With Iron Man apparently on vacation, Happy tries to tackle the Unicorn who has broken into Stark Industries but he is badly injured and ends up in a hospital. Next day, he is no longer considered in danger. Pepper visits him and tells him that she misses him.
Worried that he has not had a date with Pepper for a long time, Happy asks his boss for his help but it ends up with Stark taking her out. Next day, Happy takes matters in his own hands and Pepper accepts his invitation to a movie because she was far from impressed by her date with her boss.
Happy try to enter Stark's office from the outside window because his boss has locked himself up after a heart failure but he gets captured by the Black Knight. Iron Man saves him from a deadly fall after the villain has released him above the factory. When Iron Man tells them that their boss has left town and put him in charge, Happy and Pepper get suspicious.
Tony Stark informs Happy and Pepper that the recent sabotages in his factories are liable to lead his company to bankruptcy but they both choose to say with him.
Happy and Pepper are worried that Iron Man may not be able to save Tony Stark from the Melter.
Happy notes once more how he actually never gets to drive Tony stark anywhere.
Arriving at his penthouse, Stark and his chauffeur surprise a thief calling himself the Scarecrow as he's looting his safe. Happy tries to stop him but all he's left with is a torn piece of his costume.
After Pepper makes fun of Happy's jacket, they both get the visit of an injured Captain America who came to see Iron Man. When Cap disappears, they use Stark's tracer to locate Iron Man and tell him about it. They find him at a power plant where they both dangerously get caught a battle between the two Avengers.
As officials are getting concerned about Tony Stark's whereabouts, Happy and Pepper are worried that something terrible has happened to their boss and suspecting that Iron Man is hiding something. Despite the Golden Avenger rescuing Pepper from Hawkeye, Happy still does not trust the hero.
After one month of Stark's absence, they both give their resignation to Iron Man and help the police investigate on the Golden Avenger. Happy breaks into Stark's estate and he finds his ex-boss alive in his bed. When Pepper arrives, Stark tells them that the doctor ordered absolute rest, yet he and Pepper still don't trust Iron Man. Right after they leave, Stark's house is destroyed by a strange ray and everyone is convinced that he is dead.
After a few weeks, Stark shows up at the plant, putting an end to the allegations of his death. He announces to Pepper and Happy that he secretly got engaged to a Boston debutante, much to his chauffeur's delight.
Now that Stark is engaged, Happy dares to ask Pepper in marriage but she tells him that she is not ready yet. On their way back, they are captured by the Black Widow and Hawkeye. After Iron Man has rescued them and their boss shows up unharmed, Happy sees that Pepper is still in love with Stark.
Happy comforts his wife after hearing from the seeming death of Iron Man.
Feeling more than useless after Tony Stark has refused to let him run the test for his one-man submarine, Happy decides to quit his job takes to plane to Ireland to visit his grand-father. He gets a visit from Iron Man who tries to convince him to come back, but it's a call from Pepper that makes him change his mind.
Happy invites Pepper out to dance, but although she accepts, he is disappointed that she offers their boss to come along. Some time later, Iron Man has accepted a challenge by the Titanium Man and Tony invites Happy and Pepper to Alberia to attend the event. As the battle begins, Happy wonders why Tony is not attending. After a first round where Titanium Man clearly dominates, Iron Man charges Happy to track down Countess Stephanie de la Spiroza and recover the transistor device she has stolen. After getting it back, he rushes to the battleground to hand it to Iron Man, but a strong blast from Titanium Man critically injures him. In his last moments of consciousness, Happy realizes that Pepper actually loves him and that Tony Stark is Iron Man. An ambulance takes the comatose victim to the hospital where the doctors are rather pessimistic about his chances to survive.
