Apollo is the son of Zeus (Greek God of the Sky) and Leto, the twin brother of Artemis (Greek Goddess of the Moon), the Greek God of the Sun, Music, Poetry and Prophecy, a recurring character in the Rick Riordan book series Percy Jackson and the Olympians and The Heroes of Olympus and the main protagonist and narrator of their sequel series The Trials of Apollo.
He became God of the Sun after the previous one Helios faded. He also defeated the dragon Python.
Apollo first appears in the third Percy Jackson and the Olympians book "The Titan's Curse" where he is summoned by Artemis to escort Percy, Grover Underwood, Nico and Bianca di Angelo (son and daughter of Hades, Greek God of the Underworld), Thalia Grace (daughter of Zeus) and the Hunters of Artemis to Camp Half-Blood. During the trip, Apollo encourages Thalia to drive the Sun Chariot (in the form of a bus).
In The Heroes of Olympus Apollo is banished from Olympus by Zeus to Delos (Apollo and Artemis's birthplace) as punishment for revealing the Prophecy of Seven too early.
In the first The Trials of Apollo book "The Hidden Oracle", Apollo is transformed into a mortal teenager named Lester Papadopoulos by Zeus and is banished to Earth. Following this, Apollo, accompanied by a 12-year-old demigod named Meg McCaffrey (a daughter of Demeter, the goddess of agriculture) to Camp Half-Blood where he lives in the cabin that houses his demigod children. He also learns that a being called The Beast (who had been responsible for killing Meg's father) is planning to destroy the Oracles. Near the end of the book, Apollo learns that the Beast is the Roman emperor Nero, a member of The Triumivate Holdings (a group made up of the three worst Roman emperors). He also discovers that Meg is Nero's stepdaughter, who believes that Nero and The Beast are two separate people.
In the second book The Dark Prophecy, Apollo along with Meg (who ended her alliance with Nero), Leo Valdez and Calypso battle the second member of The Triumvate Holdings, Commodus.
In the third book, Apollo battles the third member of The Triumivate Holdings, Caligula.
- It is revealed in the first Trials of Apollo book "The Hidden Oracle" that Apollo is bisexual as he says that he has had thirty three mortal girlfriends and eleven mortal boyfriends (among them Darren Knowles, the mortal father of Kayla) and that his two greatest loves were Daphne and Hyacinthus (the latter of whom Apollo accidentally killed with a discus and whose blood created the flower Hyacinth).