Born in Wales in the mid 1700's, Isaac Davis became one of the trusted advisors of Kamehameha the Great. While serving with an American company under the leadership of Captain Simon Metcalf, Davis served aboard the small ship Fair American. In 1790, having come from the Pacific Northwest, Davis' ship was attacked while conducting trade along the Kona coast of Hawai'i Island. It is said that everyone on board the ship died, except Isaac Davis.
While recovering from his wounds, he was brought to Kamehameha, who had him accompany John Young, who at the same time had become stranded on the Island. Together, Davis and Young would serve as advisors to the powerful chief. Through fighting alongside Kamehameha and his warriors and serving as a intermediary with foreign traders, Davis was given great authority in Kamehameha's realm. At one point, Davis, called 'Aikake by Hawaiians, became the high chief for O'ahu.
It is clear that Isaac Davis and Kamehameha became close friends. Ebenezer Townsend of the Neptune noted in 1798 that,
In 1810 he negotiated terms of peace for Kamehameha with Ka'umu'ali'i, the king of Kaua'i. When Ka'umu'ali'i journeyed to Honolulu on board a foreign vessel to see Kamehameha, some lower chiefs conspired to kill him and proposed to Kamehameha that a sorcerer perform this deed. The king refused and even had the sorcerer slain. The chiefs then hatched a plot to kill Ka'umu'ali'i secretly as he journeyed into the interior. Learning of these plans, Davis warned Ka'umu'ali'i to return on board ship. Shortly thereafter, Davis died by poisoning, possibly in retaliation for this act of loyalty to Ka'umu'ali'i
John Young adopted the children of Isaac Davis and later made them heirs when he died.