During the interstellar Kree-Skrull War, the Kree Captain Mar-Vell fell in love with the Skrull Princess Anelle. She bore a child, Dorrek VIII, but when her father learned the identity of the infant's father, the Emperor ordered the baby's death. The child's nurse escaped with him to Earth, where she established human identities for both of them. He was raised as human "Teddy Altman" without knowing his alien origin, and when his powers manifested, Teddy believed he was a mutant. He shared his secret with his friend Greg Norris, who exploited Teddy and tried to use his powers to plunder Avengers Mansion after the Scarlet Witch destroyed it. Teddy refused; shortly afterwards, he encountered the time-traveling Iron Lad, who recruited Teddy and two other teenaged heroes to form the Young Avengers, inspired by the celebrated Avengers super-team (In fact, Iron Lad chose recruits who were all somehow connected to the Avengers, whether they knew it or not). During their time together, Teddy, code-named "Hulkling," began a romantic relationship with teammate Asgardian (later called Wiccan).

When the Young Avengers made their activities public, Avengers founders Captain America and Iron Man resolved to shut them down, confronting them at Avengers Mansion. Iron Lad's future self, long time Avengers foe Kang the Conqueror, arrived shortly thereafter. During the ensuing battle, Iron Lad was forced to return to his native era to save the timestream. With Kang defeated, the Avengers ordered the would-be heroes to give up their adventuring; but Kate Bishop supplied the youths with new uniforms and other resources, and they defeated such criminals as Shocker and Mr. Hyde. Despite this, the Avengers once again ordered their youthful counterparts to give up their costumed identities for their own safety.

The teens regrouped to decide their next step, but were attacked by the Super-Skrull, who exposed Hulkling's mother as a Skrull before killing her and kidnapping Teddy. He took the boy to his lair, where he tried to contact the Skrull Empire. The Super-Skrull began to reveal the truth of his origins to Teddy, but was interrupted when the Young Avengers arrived. The battle was short-lived, as a group of Kree soldiers also intervened, demanding the son of Mar-Vell be handed over to them. Teddy refused to leave Earth with either the Skrulls or the Kree, and despite the Avengers promising to protect him, Hulkling unintentionally ignited a new Kree-Skrull War. With his legendary heritage revealed to him, Hulkling remains a proud member of the Young Avengers. Recently the Young Avengers were apprehended by S.H.I.E.L.D.. Captain America with Falcon helped Teddy and the Young Avengers escape, when they all seemed to have joined the Anti Registration Act.