McCann was born in Chicago, Illinois on December 8, 1956, and was raised by her mother, a school teacher, and her grandmother.
[2] Originally interested in political science and a legal career, McCann was inspired by professors such as David Zarefsky to pursue public relations.
[3] McCann joined Leo Burnett Worldwide, a Chicago-based advertising agency, after graduating from college in 1978.
[1][5] During her tenure as CEO, Starcom's client billings exceeded $26 billion and the company grew to over 6,000 employees.
[6] McCann was responsible for strategic planning and financial management as well as overseeing clients in the United States, Canada, and Latin America.