Pepper worked in finance at Stark Industries when she found an error in Tony Stark's calculations. She rushed to Tony to correct the mark forcing her way to see him past bodyguards using pepper spray. Tony was impressed and hired her has his Personal Assistant naming her Pepper as a joke.
Pepper Potts is Stark's personal secretary and budding love interest. He asks her to help him take his old arc reactor out and to put in a new one. Tony tells Pepper to get rid of the old model since he's not a sentimental person, but she kept it inside a glass box with a special border around it reading, "Proof That Tony Stark Has A Heart". In the charity event, Tony then leaves to dance with Pepper and they share a moment together in the moonlight and almost a kiss. Tony tries to talk Pepper into helping him, believing that nothing else matters but stopping the people who he put in harm's way. Pepper is moved by Tony's dedication, and agrees. She goes into Obadiah's office with a tiny piece of equipment designed to copy files from the computer. As Pepper sifts through stored files, she finds a video from the terrorists proving that Obadiah was responsible for Tony's capture. In the battle against Iron Monger Tony instructs Pepper to overload the building's Arc Reactor, which will generate a shockwave strong enough to knock out the Iron Monger's suit. Pepper is hesitant, believing that Tony could also be killed. Tony manages to keep fighting while she builds up power to the Reactor. The Arc explodes, taking out Obadiah and injuring Tony. But the energy wave from the Reactor also manages to re-charge Tony's heart battery, saving him from imminent death.
Iron Man 2
Pepper is promoted to CEO of Stark Industries by Tony after he realises that the palladium core of his arc reactor is killing him. She decides he needs a new assistant and when "Natalie Rushman" arrives to have Tony give Pepper the company he decides he wants Rushman as his assistant. After watching Tony screw everything up, but his final battle with Ivan Vanko is a success, so she resigns and hands the company back over to Tony.
Pepper Potts is seen having a romantic date with Tony Stark at the top floor of the Stark Tower, but they're interrupted by the sudden arrival of Phil Coulson, who has to crash J.A.R.V.I.S.'s systems in order to get in the tower, since Stark is trying to close him outdoors. Pepper has befriended Coulson during their previous meetings, and asks him about his personal life, as well as convincing Stark to listen to him and to read what documents he's giving him. Pepper is well aware of The Avengers Initiative, due to Stark's inability to keep a secret (especially a government-related one that he cares little for), and she manages to convince her boss and boyfriend to help S.H.I.E.L.D. save the world from Loki Laufeyson. Later, when the Chitauri have started their invasion, Pepper is on a private plane, safe from the battle. Stark, before sacrificing himself to destroy a nuclear strike sent on Manhattan, tries to call her on the phone, but she doesn't hear it and doesn't answer. After the battle, when the Avengers are disbanded and everyone comes back to their normal life, Pepper rejoins with Stark, helping him redesign the heavily damaged Stark Tower.