Kaʻahumanu was the queen consort and later regent of the Kingdom of Hawaiʻi, wielding significant influence and authority. As King Kamehameha I's favored wife, she was his confidante and a powerful political partner. Her impact extended beyond his reign, as she governed alongside his successors, shaping Hawaiʻi's future.

She served as the foster mother of King Kamehameha II, securing her regency. In 1820, she welcomed Christian missionaries, and five years later, embraced Christianity as Elizabeth, inspiring many Hawaiians to convert.

In 1826, Kaʻahumanu played a key role in negotiating Hawaiʻi's first treaty with the United States, marking the start of formal diplomatic relations.