Henry Ivan Neilson was born in Québec in 1865. Neilson became a marine engineer, and was for a number of years in the service of the Canadian Pacific Ocean Steamships.
Neilson turned to painting in 1897, and studied art at the Glasgow School of Fine Arts, at the Académie de la Clausse, Paris, and at St. Giles Academy, in Brussels.
Neilson returned to Canada in 1910 and was elected an academician of The Royal Canadian Academy of Arts.
He painted mostly landscapes, but also incorporated figurative subjects in some of his works. Later in life he devoted much of his time to etching.
Neilson taught at the New School of Fine Arts at Québec in 1921, and in 1929 he became principal.
Neilson is represented in the National Gallery, Ottawa, and in the Québec Museum, among others.
Neilson died in Québec in 1931.