Whitiopai signed the Cook Strait (Henry Williams) sheet of the Treaty of Waitangi on 26 May 1840 in Manawatū. He was a rangatira (chief) of Ngāti Raukawa. Reverend Rawiri Te Wanui was his cousin.
Whitiopai was baptised on 26 January 1842 by the missionary Octavius Hadfield. He died at Ōtaki in 1858.