Haruki is a warrior and native islander who comes to the Island to claim or pledge his worthiness to his chief's daughter in Gilligan's Mother-in-Law. Haruki appears on the island during the marriage festival and presents himself as a rival to Gilligan, who the chief's daughter has chosen as a husband. Although Gilligan is not interested in marriage or the rivalry, the Chief decides to test their worthiness with a tournament of spears. Haruki lets Gilligan go first and is ecstatic when his aim is horrible. However, Gilligan does manage to knock coconuts loose that knock Haruki out cold. The chief's daughter rushes to his aid and chooses him as her husband, but seeing as how Gilligan bested him, Haruki tries honoring Gilligan with a "best man" position in his wedding ceremony, letting the Professor know the honor is contested by poison darts at six paces. Tired of the games, Gilligan turns down the honor.
- Haruki is portrayed by Eddie Little Sky, who also played the Witch Doctor.
- One can clearly hear Eddie Little Sky's Native American Indian tongue in his dialect. Unlike the Chief's "unga-bungas," Eddie's dialect flows more naturally.
- There seems to be no consistency to the pronouncing of Haruki's name. It is pronounced Haruki by the Chief and by the Professor repeatedly at the start. When Ginger comes on to Haruki, he says his name is Haruka, which Ginger then starts using. After Haruki is knocked out by the coconuts, the Chief and his wife call him Haroki. In the final moments, the Professor starts calling him Hiroki!