Stronach was a member of the board of directors of Magna from 1988 until 2004. She became a vice-president of the company in 1995 and executive vice-president in 1999, until her appointment as president and chief executive officer. She has chaired the boards of Decoma International Inc., Tesma International Inc., and Intier Automotive Inc., all in the auto parts sector. She was a founding member of the Canadian Automotive Partnership Council and served on the Ontario Task Force on Productivity, Competitiveness and Economic Progress. She previously served as a director of the Yves Landry Foundation, which furthers technological education and skills training in the manufacturing sector.