Blessed and cursed with extraordinary genius, Tony Stark is the son of inventor and defense contractor Howard Stark, and geneticist & educator Maria Stark. The Starks were developing a biological personal armor coating when a lab accident with a regenerative virus fatally infected Maria. The virus mutated her unborn child, Tony, growing additional neural tissue throughout his body which augmented his intelligence while causing chronic pain. Maria died, but Howard saved Tony by coating him in their bacterial bio-armor, which consumed ordinary skin but not Tony's constantly regenerating neural flesh. Business rival Zebediah Stane married Howard's scheming ex-wife Loni, with whom he stole Stark's company, and spent years trying to seize the bio-armor. As a teenager, Tony befriended fellow prep school student Jim Rhodes and began developing his own "Iron Man" armor technology. Becoming a wealthy celebrity and science prodigy, young Tony founded multi-billion dollar design and manufacturing corporation Stark International. He also became an infamous playboy, alcoholic, and womanizer, suffering from recurring depression and secretly learning he was dying from an inoperable brain tumour.
When Stark and his shifty cousin Morgan were taken hostage along with other civilians by Guatemalan guerrilla terrorists, their captors demanded Stark's technology in exchange for the hostages' freedom. They killed Morgan when Tony refused to cooperate. Pretending to acquiesce, Stark built makeshift armor and defeated the terrorists with it. Years later, Stark used the new Iron Man armor to save the President from an assassination attempt, becoming a bigger celebrity than ever, but refusing to sell or mass-produce his armor technology. When Latverian ambassador Golog tried to steal Stark's "Irontech" with the covert approval of intelligence agency S.H.I.E.L.D., Stark fought off Golog's Mandroids with the aid of Spider-Man. Spurred by his tumor to make the most of whatever time he had left, Stark began doing more charitable good works, relocated to his Manhattan property and agreed to join the Ultimates, a S.H.I.E.L.D.-sponsored superhero team. Forming an unlikely friendship with anti-corporate teammate Thor, Stark helped subdue the monstrous Hulk and save Earth from the extraterrestrial Chitauri. Tony began dating teammate Natasha Romanov (Black Widow) and eventually proposed to her, creating new armor for her as an engagement gift; however, when a traitor within the ranks helped an army of foreign super-soldiers defeat the Ultimates, Natasha was apparently revealed as the traitor when she turned on Tony during the assault. Tony turned the tables on her, using the nanites he had given her to enable her to control her armor against her, paralyzing her and downloading information direct from her brain to his.