Membertou was the leader of a small band of Mi'kmaq whose hunting and fishing territory included the area of Port-Royal.In addition to being
sakmow or political leader, Membertou had also been the head
autmoin or spiritual leader of his tribe — who believed him to have powers of healing and prophecy. Both Lescarbot and explorer
Samuel de Champlain wrote of having witnessed him conducting a funeral in 1606 for Panoniac, a fellow Mi'kmaw
sakmow who had been killed by the Armouchiquois or
Passamaquoddy tribe, of what is now Maine. Seeking revenge for this and similar acts of hostility, Membertou led some 500 warriors in a raid on the Armouchiquois town, Chouacoet, present-day
Saco, Maine, in July, 1607, killing 20 of their braves, including two of their leaders, Onmechin and Marchin. He first met the French when they arrived to build the
Habitation at Port-Royal in 1605, at which time, according to the French lawyer and author
Marc Lescarbot, he said he was over 100 and recalled meeting
Jacques Cartier in 1534. Membertou became a good friend to the French. Father Biard described him as being tall and large limbed compared to the other natives. It is also said that he had a beard in contrast to the others who removed any facial hair. Also, unlike most
sakmowk who were polygamous, Membertou had only one wife, who was baptised with the name of "Marie". Lescarbot records that the eldest son of Chief Membertou had the name Membertouchis (Membertouji'j, baptised Louis Membertou after the then-King of France,
Louis XIII), while his second and third sons were called Actaudin (absent at the time of the baptism) and Actaudinech (Actaudinji'j, baptised Paul Membertou). He also had a daughter, given the name Marguerite. After building their fort, the French left in 1607, leaving only two of their party behind, during which time Membertou took good care of the fort and them, meeting them upon their return in 1610.