Final answer:
Louis Riel led the armed uprising and seized Fort Garry during the Red River Rebellion of 1869-1870, which was instrumental in the creation of the province of Manitoba and the recognition of Métis rights.
Step-by-step explanation:
The individual who led an armed uprising and seized Fort Garry was Louis Riel.
This event took place during the Red River Rebellion of 1869-1870, where Riel and his followers, primarily the Métis and other mixed-ancestry groups, were asserting their rights and looking to negotiate with the Canadian government regarding the transfer of the vast territory of Rupert's Land from the Hudson's Bay Company to Canada.
Riel established a provisional government at the fort and took control, which was a pivotal moment in the creation of the province of Manitoba and the recognition of Métis rights.