Lewis was the executive director of Alberta Ballet for four years, leaving in August 2005 after reportedly clashing with the company's board. She previously worked for Canada's federal government.
"This is an exciting time of growth for the CPO, " Lewis said in a statement. "I am thrilled to work with the board, staff, musicians, chorus, volunteers, supporters, partners, and the community to achieve the organization's vision."
Board chair David Payne said, "Under Ann's leadership, the board expects that the organization will strengthen its artistic vision by reaching out to a broader range of audiences within Calgary and surrounding communities."