His father is never introduced. The anime suggests that his father was once a Pokémon Trainer, but it is unclear whether he is still living. There has been much discussion in the fandom as to the identity of Ash's father, though the writers have chosen to not focus on this aspect of Ash's life. Common characters put forward by fans for the role are Giovanni (leader of Team Rocket), Professor Oak and Silver. In Pokemon Live!, Ash's mom told Ash that Giovanni had once been her boyfriend, and that he was Ash's father. However, this has never been officially acknowledged.
An interview with the series' storyboarder confirmed Ash's father is a trainer in journey. According the same storyboarder, Ash's dad might or might not be introduced at the series, depending the necessity of turning Ash more mature.