Kitsap was born to a Skopamish (Lushootseed: sxʷq̓ʷupabš)[4] man of Yakama ancestry, who had married into the Suquamish,[5] giving him strong ties to the Green River people.

[7] Kitsap lived in a longhouse on Bainbridge Island, located west of Restoration Point[5] on Rich Passage.

Two Suquamish men, one of whom was likely Kitsap, led a welcoming procession in canoes, and they eventually were invited to board the Discovery.

One of Seattle's grandsons, Sam Wilson, said that Kitsap was inspired to build the Old Man House by a dream where he and the Suquamish could greet the Europeans when they returned.

Kitsap invited workers from across Puget Sound, as far south as the Cowlitz people, holding competitions to raise the massive logs into place.

It may also have been associated with the creation story of Agate Pass, in which an eagle and a serpent widened a narrow channel into the broad passageway during a battle.

[8][14] By 1815, Kitsap was middle-aged, and was described to be a "tall, broad and thick man" and a "ruthless, domineering leader who killed his own uncle".

[5] His ancestry, as well as the ownership of the Old Man House and the older longhouse on Rich Passage, showed that he was wealthy, and his strength was also famous.

Circa December 7–8, they landed at a Suquamish village, seeking to speak with a known chief, possibly Kitsap, but encountered few people.

[16] Kitsap wanted to create an alliance to defend against the Cowichans of Vancouver Island, and envisioned a coalition stretching from the Columbia River to Puget Sound, with the Old Man House at the center.

[b][18] Contingents from the Stkamish, Sammamish, Puyallup, Nisqually, Squaxin, Chehalis, Cowlitz, and more joined the Suquamish in the attack in more than two hundred war canoes.

[19] On the way north, the coalition raided Snohomish and Skagit encampments for supplies before continuing past the San Juan Islands.

Through the fog, the Suquamish force heard the Cowichan celebrating a successful raid against the S'Klallam, their canoes filled with slaves and plunder.

[20] When Kitsap's oldest son visited Fort Langley to trade, he met with Shashia, a leader of the Cowichan, who put him under his protection.

Thirty Suquamish and a leader, likely Kitsap, visited the second James McMillan expedition on July 6, 1827, who were camping at Point Jefferson (Lushootseed: sqʷayupšəd).

[22] The Suquamish party brought trade goods, although McMillan felt threatened by their presence, worried that their newfound confidence may have led them to kill them and take their belongings.

[21] On June 29, 1829, Kitsap may have been the "old Indian" and chief of the Suquamish who met with a contingent of armed settlers led by one Alexander McLeod.

[24] Despite this, he is more remembered by the Suquamish for his strategic vision and leadership, than his wealth and strength,[8] and his ability to bring together an alliance to achieve "what none could have accomplished alone".