Third-born child and eldest son of King Jaehaerys I Targaryen and Queen Alysanne, born on Dragonstone in 55 AC, Aemon was named his father's heir from the moment of his birth. The night after he was born, a dragon's egg was laid in his cradle at the queen's urging, and when Jaehaerys carried the infant to the ramparts of the Red Keep, the smallfolk of King's Landing are said to have raised a roar that carried across the narrow sea. He was a grave and obedient child, tall and handsome even at seven, with eyes pale as lilac and hair that shone like white gold; his mother liked to say his first word had been "Why?" Though shyer and milder than his fierce younger brother Baelon, the two were inseparable, training together in the yard to the delight of the crowds that gathered to watch.
In 62 AC, Jaehaerys formally invested the boy as Prince of Dragonstone. The king had meant to wed him to his elder sister Daenerys, but she died young in 60 AC, and so in 70 AC Aemon married instead his aunt, Lady Jocelyn Baratheon, in a ceremony as grand as the Golden Wedding. Their only child, Princess Rhaenys, was born in 74 AC. Aemon proved himself a worthy heir: victor of the squires' melee at Duskendale and afterward knighted, claimant of the fierce dragon Caraxes, and named master of laws and lord justiciar on his six-and-twentieth nameday. In 83 AC he rode beside his father and Baelon to burn Prince Morion Martell's invasion fleet from the sky, winning the Fourth Dornish War in a single day without the loss of a man.
In 92 AC, Aemon led the assault on the Myrish pirates who had seized the eastern half of Tarth in the bloodbath then ravaging the narrow sea. Joining Lord Cameron Tarth at his mountain camp at the island's heart, the prince was struck in the throat by a Myrish scout's crossbow bolt loosed at the Lord of Tarth, and drowned in his own blood at seven and thirty. His death threw the succession into doubt, for his sole heir was a daughter, then pregnant with her first child. Jaehaerys passed over Rhaenys for his second son Baelon, a choice the Great Council of 101 AC would later affirm, and for which the fool Mushroom dubbed her "The Queen Who Never Was." Through Rhaenys's marriage to Lord Corlys Velaryon, Aemon became posthumous grandsire to Laena and Laenor, whose blood would course through both sides of the Dance of the Dragons.