Sayer enlisted as a coureur des bois with the McTavish, McGillivray & Company on April 7, 1818, as was registered by the notary J.-G. Beek at Ste Anne, Bout de l'Isle, in the west of the Island of Montreal.
From 1828 to 1829, he worked for the Hudson Bay Company as a Bowsman at Fort Pelly in the Swan River District and then stayed on as a Steersman from 1829 to 1832.
In 1832, he was freed from his service in the Hudson Bay Company and moved to Grantown, near the Red River Settlement.
On March 2, 1835, according to the St. Francois Xavier Catholic Church marriage records,[1] Sayer married Josephte Frobisher, the elder daughter of fur trader Alexander Frobisher and his Cree wife, on March 2, 1835, at St. Francois Xavier.
[2] Sayer had been trading to Norman Kittson, now in Pembina, North Dakota, which was in direct violation of the Hudson Bay Company's monopoly.
In 1849, Chief Factor John Ballenden arrested Sayer, André Goulet, Hector McGinnis, and Norbert Larond of Grantown as they were about to leave on a trading trip to Lake Manitoba.
Judge Adam Thom, under immense pressure from the presence of numerous armed Métis, levied no fine or punishment.