The exhibition features a series of black and white photos of Leeds city centre in the 1950s.
Wallis, a childhood friend of actor Peter O'Toole, began his career as a press photographer for the Yorkshire Evening Post.
The exhibition, 'Ralph Wallis: Is this seat taken?' runs until 20 April.
Wallis, 83, who now lives in Canada, said: "Similar to [industrial artist] Edna Lumb I found Leeds, with all its soot covered buildings and incredible street children of all shapes and sizes, just screaming out to be photographed.
"As in those dark days, which I loved as a young photographer, Leeds was made for us."
The exhibition has been curated by Wallis' niece Bianca Wallis-Salmon
A display of work by photographer Ralph Wallis has opened as part of Leeds College of Art's 170th anniversary celebrations.