Simon Krieger was vice-president to Republic Oil & Natural Gas before it became Roxxon Oil. Along with fellow board members Hugh Jones, John T. Gamelin and Jonas Hale, he was responsible for the deaths of Howard and Maria Stark in a plot to take over Stark Industries.
After Tony Stark proved to be capable of running the Company, despite his agent, the Saboteur trying to undermine Stark Industries' Efforts to hold true to their government contracts, he tried to buy Iron Man, not knowing that Stark himself is Iron Man. To find out what Krieger's plans were, the Golden Avenger played along and seemingly prevented Stark to attend a meeting on the newly assembled Helicarrier.
Krieger disguised himself as Tony Stark and attended the meeting in his place. With the help of his agents, the Dogs of War, he took the politicians aboard the carrier hostage and demanded, live on camera, one hundred billion dollars ransom for them in an attempt to ruin Tony Stark's reputation so Republic Oil can take over Stark Industries.
He had the Dogs of War turn off the cameras as Iron Man came for the rescue. However, Happy Hogan was able to overwhelm Greyhound of the Dogs of War and turn the cameras on again, just in Time for Krieger's unmasking. He was arrested and assassinated in jail by an unknown person hired by Hugh Jones.