After completing his B.A., M.A. and Ph.D. degrees in Chinese and Japanese languages and literatures, Dr. Walls began his academic career teaching Chinese language and East Asian cultures at the University of British Columbia (1970-78) and the University of Victoria (1978-85). In addition to teaching, he founded and directed the Centre for Pacific and Oriental Studies at Victoria. From 1981 to 1983 he served as First Secretary for Cultural and Scientific Affairs at the Canadian Embassy in Beijing, and from 1985 to 1987 he was Senior Vice President of the newly established Asia Pacific Foundation of Canada, where he founded and developed the first Education and Cultural Affairs programs.

In September, 1987, he joined Simon Fraser University, where he founded and directed the David Lam Centre for International Communication until his retirement. He was also Founding Director of SFU's Asia-Canada Program, an interdisciplinary minor or intensive minor program for undergraduate students. He retired from university in 2006, after 36 years of teaching Chinese language and East Asian cultures.

He was a founding member of the Board of Directors of the David Lam Institute for East-West Studies at Hong Kong Baptist University, and has been a director of the Dr. Sun Yat Sen Classical Chinese Garden Society, S.U.C.C.E.S.S., and the Tzu Chi Education Foundation.  He serves on the Government of British Columbia’s Multicultural Advisory Council, and on the Chinese Community Advisory Group for the Lower Mainland B.C. Canadian Red Cross Society, and is currently a director of the Canadian Society for Asian Arts and the Chinese Canadian Historical Society of British Columbia.