Goten is born after Goku's death at the Cell Games and debuts in the last saga of Dragon Ball Z, then returns in GT and Super. This page follows him arc by arc; the full profile is in Goten's profile. His is the story of a child prodigy who becomes, together with Trunks, the key card against Majin Buu, and then drifts further and further to the sidelines as he grows up.
Dragon Ball Z
Majin Buu Saga (episodes 200-291)
Goten appears in the anime from episode 201, a pint-sized copy of the father he has never met. In the Majin Buu Saga, in episode 206, Gohan starts training him for the World Martial Arts Tournament and discovers his little brother can already turn Super Saiyan. Soon he learns to fly alongside Videl and, at the tournament, meets Goku for the first time, back from the afterlife for a day. In the junior final he matches Trunks, transforms as well, but loses when his feet touch the stands. The pair then sneak into the adult division inside the Mighty Mask costume, until Android 18 unmasks them and gets them disqualified.
When Buu awakens and the adults fall one after another, Goku and Piccolo teach the two kids the Fusion Dance. In episode 251, after two botched attempts, Gotenks is born, rushes off cocky to face Buu and comes back battered. After training in the Hyperbolic Time Chamber they fuse again: in episode 260 Gotenks goes Super Saiyan 3 and puts Buu on the ropes, but the fusion runs out and the demon later absorbs him. Wished back to life, Goten lends his energy to the final Spirit Bomb. Ten years later he and Trunks are pushed into entering the next tournament.
Dragon Ball GT
Black Star Dragon Ball Saga (episodes 1-16)
At the start of GT Vegeta picks him to go into space with Goku and Trunks, but Goten has no interest. In episode 2, part of the Black Star Dragon Ball Saga, the ship takes off with Pan in his place. Goten stays on Earth, where his mind is mostly on girls, and on Valese in particular.
Baby Saga (episodes 17-40)
When the parasite reaches Earth in the Baby Saga, Goten is the first Saiyan to face him. In episode 26 he transforms to impress Valese, but Baby slips into him through a wound and uses him to take Gohan too. In episode 38, freed with the Sacred Water, he gives his energy to Super Saiyan 4 Goku along with Gohan, Trunks and Pan.
Super 17 and Shadow Dragon Sagas (episodes 41-64)
In the Super 17 Saga he fights the villains who escaped from Hell, and in the Shadow Dragon Saga he takes on one of the dragons and is beaten with ease. In episode 64, when Goku leaves with Shenron, he and Gohan comfort their mother.
Dragon Ball Super
Battle of Gods Saga (episodes 1-18)
In the Battle of Gods Saga Goten and Trunks go looking for a wedding present for Gohan and Videl. At Bulma's party, in episode 7, they fuse into Gotenks against Beerus, who puts him in his place with a finger tap, the way you would punish a child. In episode 9 the two bring out the Dragon Balls, and Goten takes part in the ritual that turns his father into a Super Saiyan God.
Future Trunks Saga (episodes 47-76)
In episode 49 Chi-Chi stops him so he will study. In the Future Trunks Saga we learn that in the alternate future Goku Black killed that world's Goten along with Chi-Chi. In episode 75 his mother once again objects to him training with his father.
Universe Survival Saga (episodes 77-131)
In episode 77 he sneaks out with Goku and ends up sparring with Trunks. In the Universe Survival Saga he is left out of the Tournament of Power as still too immature, and with Trunks he watches over Android 17's island: in episode 131 the two come back battered after stopping a group of poachers.
Movies
In Dragon Ball Super: Super Hero Goten is a high-schooler playing superhero with Trunks under the name Saiyaman X-2; in the final battle they botch the fusion and produce a failed Gotenks.
Our take
Seen saga by saga, Goten's arc is short but clear. In the Majin Buu Saga he is almost a lead: his first Super Saiyan, reached without drama, says the new generation starts where their fathers left off, and Gotenks brings comedy to a saga that risked turning too dark. From then on, though, the series never quite know what to do with him.
In GT he is a teenager who prefers dates to training, in Super he sits out the biggest tournament. It is a limit, but also a consistent choice: Goten never had his father's hunger for fighting. He works best as half of a duo with Trunks, and his best moments always come in pairs.
Did you know? In Funimation's English dub, Kara Edwards voiced both kid Goten and Videl, his future sister-in-law.
For his family, see Goku saga by saga and Chi-Chi saga by saga; for his lifelong friend, Trunks' profile.