Splash became ill last week and died Tuesday at the San Diego theme park, SeaWorld public affairs officials said.
The 15-year-old male orca suffered from epilepsy and was given medication daily, park officials said. Last week, Splash's health began to deteriorate and his appetite dropped.
Results from a necropsy performed Tuesday won't be known for several weeks, park officials said.
The last killer whale to die at SeaWorld was a 25-year-old female named Bjossa who succumbed to a lung infection in October 2001.
Born in captivity at a Canadian marine park in 1989, Splash had been at SeaWorld since 1992.