He came to New France as a teenager and was captured in an Iroquois raid, but was adopted by his captors and became accustomed to their way of life. After two years living with the Iroquois he returned to New France, and he journeyed to the fur-trading regions of Lake Michigan and Lake Superior with his brother-in-law Médard des Groseilliers. However, as they did not have a license to trade furs, the officials in New France confiscated their furs and fined them when they returned in 1660.
In 1668 they defected to the English, leading two English merchant ships into Hudson Bay from the north. This eliminated the necessity of travelling to fur-trading lands by land from the St. Lawrence region. The mission was successful and in 1670 the English founded the Hudson's Bay Company.
Radisson attempted to return to New France, but he was now considered a traitor. He lived in England until his death in 1710.