Before joining York University, Lehrer was an Assistant Professor at Brock University, Canada, and at SUNY Buffalo, USA. Lehrer received a Ph.D. from University of California, Los Angeles (UCLA) in urban planning, and a lic.phil from the University of Zurich, Switzerland in art and architectural history, sociology as well as economic and social history. In the 1990s, she worked at the Swiss Federal University of Technology, Zurich, (ETH). She also was the architecture critic for one of Switzerland’s largest daily newspaper.