As a baby, Goku was sent to Earth by the Saiyans on his home planet. His Saiyan name was Kakarrot (carrot). On arrival however, he landed on his head and forgot his mission. He was found by an old martial artist named Son Gohan who decided to adopt this kid and gave him the name Goku (meaning monkey, as he had a monkey's tail). Grandpa Gohan trained young Goku to fight. They lived in the mountains until on one occasion Goku saw the full moon, and turned into a giant ape and killed his Grandpa. When Son Gohan died, Goku was left alone in the house in the woods, with the 4 star Dragon Ball from his Grandpa that he believed had the old man's spirit inside. He also had a Nyoibou (Power Pole in the US version) that could extend which Gohan left him. One day, a girl called Bulma came to Goku's house in the woods looking for the 4 star Dragon Ball, and he went to find the rest with her. Goku soon became best friends with a little monk named Krillin. When Goku was 12, they both trained with Muten Roshi at Kame House and learned famous attacks, like the Kamehameha, 'turtle attack'. Muten Roshi gave Goku a flying cloud named Kintoun (aka Nimbus).

When he was young, Goku agreed to marry a girl called Chi Chi, because he thought it meant he would get some food. They had a son who was named Gohan, after his Grandpa and appeared in the series at the start of DBZ. Goku was killed in the Saiyan saga and went for training at King Kai's planet, but was granted life when the Saiyans arrived. He was also killed in an attempt to save the world from Cell, and stayed dead for 7 years. During this time, his second son, Goten, was born. He was brought back to life again in the Buu saga. Goku's most famous attacks/techniques are Instant Transmission, Kamehameha, and Genki Dama (Spirit Bomb). His highest Super Saiyan level was Ssj4.

In DBGT, Goku was accidently wished into a kid again. In order to get changed back, he had to go on a quest around the universe for the Black Star Dragon Balls.