Sir Wilfred Thomason Grenfell was born in 1865 at Parkgate, Neston, Wirral, England, the son of Reverend Algernon Sidney Grenfell, headmaster of Mostyn House School, and Jane Georgiana Hutchison.
Grenfell moved to London in 1882 and studied medicine at the London Hospital Medical College, graduating in 1888. The Royal National Mission to Deep Sea Fishermen sent Grenfell to Newfoundland in 1892 to improve the plight of coastal inhabitants and fishermen. He married Anne Elizabeth Caldwell MacClanahan of Chicago, Illinois, in 1909. They had three children and retired to Vermont after his work in Newfoundland. In 1927, Grenfell was knighted for his years of service on behalf of the people of Newfoundland.
Grenfell died in Charlotte, Vermont in 1940.