Lazarus graduated from Midwood High School before going to Smith College. She also obtained an MBA from Columbia Business School. She joined Ogilvy & Mather in 1971 and became President of its U.S. direct marketing business in 1989. She later became President of Ogilvy & Mather New York, followed by President of Ogilvy & Mather North America. In 1995, she became president and Chief Operating Officer of the company, before becoming Chief Executive Office in 1996 and Chairman in 1997. She held the title of CEO until 2008 and continues to serves as Chairman.