He was the only son of James Bain, a bookseller, publisher and the first chief librarian of the Toronto Public Library.

Following his graduation from Jarvis Collegiate Institute, Bain enrolled in mining engineering at the School of Practical Science at the University of Toronto.

Bain joined the university staff as a junior instructor in 1897, and following postgraduate work in Zurich, Switzerland, rose through the academic ranks to become professor of chemical engineering in 1916, and head of the department in 1920.

[3] Throughout his career, Bain served as an advisor and consultant to a variety of industries engaged in chemical operations, and was also involved in numerous professional societies.

[1] In 1947, Bain was presented with a portrait of himself painted by Kenneth Forbes, in recognition of his contribution to the field of chemical engineering.