At the beginning of EarthBound, Ness is awoken from a sound sleep by the impact of the meteorite north of his house in Onett. His mother and sister are agitated, but Ness leaves to find out what happened. After meeting up with Liar X. Agerate and Pokey Minch, he returns home and tries to get back to sleep. Soon thereafter, Pokey arrives and demands that Ness help him look for his little brother, who has gone missing during the calamity surrounding the impact.
After a pep-talk from his mother, Ness, Pokey and King go back out to the hillside, where they find Picky (who reveals it was Pokey who actually ran away). They also encounter Buzz-Buzz, an insectoid warrior who has returned from the future to warn Ness of the threat that Giygas poses to the universe. It is from Buzz-Buzz that Ness learns of the prophecy surrounding his future; that he, along with the help of two other boys and one girl, will stand against Giygas and save the universe from total annihilation.
Vested with this knowledge, Ness accompanies Pokey and Picky back to their home, but is assaulted by a Starman Jr.. The alien confirms the prophecy before attacking the group. It is defeated through Buzz-buzz's massive PSI powers and Ness' physical attacks. Upon arriving at Pokey's house, Buzz-buzz is unceremoniously killed (for his alleged resemblance to a dung beetle) by Lardna Minch. Before expiring, Buzz-buzz passes on the Sound Stone to Ness, and starts him on his quest to save the world.
- Ness is the only main protagonist in the Mother series to not normally have the run ability. He can temporarily run with the aid of a Skip Sandwich or Skip Sandwich DX, however.
- Ness was originally planned to be replaced by Lucas as the character representative of the Mother series in Super Smash Bros. Melee; however, Ness reprised his role due to the original cancellation of EarthBound 64.
- Using the Don't Care naming option, possible names for Ness are "Ness", "Alec", "Roger", "Will", "Brian", "Tyler", and "Lane".
- In an early video of EarthBound 64, footage was shown of what appears to be Ness riding a Pork Bean and walking in the forest. It is speculated by fans that he would have been playable, as a 3D model of Onett was also shown.
- Ness is the only Mother character to have his game released out of Japan.
- In the original, Japanese verion dubbed MOTHER 2, when Ness enters Magicant, he appears naked (sprite seen above) instead of being in his PJ's. This is explained by nudity being a sign of purity in Japanese culture.
- Ness's name is likely a homophone of NES and an anagram of SNES, two Nintendo consoles that were out at the time.
- Ness appeared in Super Smash Bros., Brawl, and the 3DS version of Super Smash Bros. 4 as an unlockable character and starter of Melee & the Wii U version of SSB4 as a starter character along with Captain Falcon.