Ness's Father is a character in EarthBound. He is also Tracy's father and the husband of Ness's Mother. Because their neighbor Aloysius Minch allegedly loaned a large sum of money to Ness's father and was never repaid, Aloysius and Lardna Minch seem to hold a grudge against Ness's father and his family for this reason alone.
Ness's unseen father, a reference to the creator's plight in work-centered Japan, only appears as a voice on the telephone. Even in the cast roll during the game's ending credits, the telephone's sprite appears as Ness's father. To save the game, it is necessary to locate a phone and call him. He also deposits battle earnings into Ness's bank account. At the end of the game, Ness's father stops saving game progress so he can be home in time for Ness's thirteenth birthday, which allows the player to fight the final boss again. It is stated in the EarthBound Player's Guide that Ness's father works in the "hamburger industry".
Theory warning: This section contains theoretical information based on the viewpoints or research of one or several other users. It has not been officially verified by Nintendo and its factual accuracy is disputed.
When Mother was being translated for EarthBound Zero (and later for the release of Mother 1 + 2), the year the game takes place in was retroactively changed from 1988 to the early 1980s. This makes it possible that Ness's father could be Ninten, as the new dates given make it conceivable for Ninten to have a 13-year-old child in 199X. Also, being that Ness's mother has blonde hair, that means that Ness's father had to have black hair to give Ness the black hair gene. Ninten has black hair, which makes it more possible. This would also explain why Ness has psychic abilities, much like Ninten. This may also explain/be hinted by a line that Ness's father says during their first telephone conversation, "I feel like such a hero." which could refer to his own adventure instead of Ness's. ( ie He was proud that Ness was continuing his legacy of saving the world from Giygas. )