He was the son of Kuaiwa, 8th Alii Aimoku of Hawaii, and Kamuleilani. Kahoukapu seems to have followed his father Kuaiwa in the sovereignty of Hawaii. No wars nor misfortunes disturbed his reign, at least the report of none has come down to our time. He erected the nioi-wood embankment at Paka'alana at Waipi'o, Hawaii, which was a very sacred symbol of chieftainship. Only Liloa, Laea-nui-kau-manamana, & their descendants of the three highest classes (the ni'au-pi'o, pi'o, and naha chiefs) were permitted to walk upon it. It was destroyed in the 18th century when Kaeokulani, Prince of Maui, landed at Waipi'o and set fire to it, Kahoukapu's sacred threshold of nioi wood. He was also the reputed builder of the sacred pepper tree supports of the ancient Hawaiian royal residence, the Waipio Palace, a home of the Alii Aimoku of Hawaii.
His wife's name was Laakapu, who was descended from Kila, son of Moikeha of the Nanaulu-Maweke line. She was barren, and so they had no children. But being very desirous of offspring, she went to consult with Paao, the priest, about it. "Here I am," said Paao. "What shall I do to beget a child?" entreated Laakapu. "You must go and fetch a fish as an offering to the deity for yourself," said Paao. Then she went away, and having obtained a fish, she returned to Paao, saying, "There is a fish for the deity." "What sort of a fish is it?' asked Paao. "A weke," said laakapu. "Throw it away," said Paao, "the deity will not eat such a fish as that is like a rat. It's full of bones; so is a rat. It has a beard; so has a rat. It is lean; so is a rat. Go and fetch another fish."
Laakapu then brought another fish to the priest. "What fish have you?" asked Paao. "It is a moi," she answered. "Throw it away," said he. "It is a rat, the rat Makea. It lives in sea foam (hua-kai); the rat makes his covert in the house thatch (hua-hale); the moi has whiskers; so has mister rat. Bring another fish." Then Laakapu got another fish and brought it to Paao, who asked, "What fish have you?" "A squid." "Fling it away," said he; "it is the rat Haunawelu. He lives in holes under the ocean. Mr. Rat lives in holes in the rocks. Mr. Squid has arms (awe); Mr. Rat also has a tail. Fetch another fish." Laakapu then brought a maomao; but Paao declared it also was a rat. Laakapu, now discouraged and out of patience, said to Paao, "Tell me what sort of fish you want." "A paoo, that is not rat," said he. Then Laakapu brought a paoo to the priest, and in answer to his question as to what the fish was she answered, naming the fish, and then, obedient to his demand, gave it to him. Then Paao offered the fish as a sacrifice to the idol deity with the prayer, "Grant a child unto Laakapu." And in due season Laakapu gave birth to a child. But it was of doubtful sex, and she named it Kauhola-nuimahu.
This son Kauholnuimahu would succeed upon his father's death in 1405.