In 1972, he was an organizer of Heritage Toronto, a citizen's group interested in Toronto's history. Since 1975, he has written the column, The Way We Were for the Toronto Sun. He has written more than two dozen books about the history of Toronto. Among the topics covered are Toronto Transit Commission (TTC), books with old photographs, and nine books of Toronto Sketches. He also has a radio show on New AM 740. His guided walks include topics such as Toronto, Then and Now.
According to his friend Alan Parker, another columnist at the Toronto Sun, Filey is known as "Toronto's best-known historian".
Mike Filey (2018-11-17). "Memories of old Toronto". Toronto Sun. Retrieved . No, more than that, because 758 is where I grew up while attending Palmerston Public School, playing in the back laneway that ran between Lennox and Bloor Sts., going to events at the K-Club in the basement of the old church at the corner of Bathurst and Lennox and watching movies at the Metro, Midtown or, most likely, Alhambra theatres.
Alan Parker (2008-11-09). "Five Questions for Mike Filey". Toronto Sun. Retrieved . As a researcher, writer and raconteur, Mike has been chronicling the life and times -- past and present --of the beloved city of his birth for four decades. He's been called "Toronto's best-known historian" -- and deservedly so.