Leo-Arthur Kelmenson was the Chairman of FCB Worldwide, a leading global advertising agency. He played a leading role in the company's international expansion and in the development of overall corporate strategy. He also served on the Board of Directors of its parent company, True North Communications Inc., the advertising agency holding company, until its eventual sale to InterPublic Group, the world's third largest advertising agency holding company.

He previously served as Chairman of the agency and focused his energies on the DaimlerChrysler account. Leo first joined Kenyon & Eckhardt in 1967 and was named President in 1968 and Chief Executive Officer the following year. He was elected Chairman/CEO in 1984 and held that title at the time of the agency's merger with Bozell in 1986. Earlier, Leo had been Executive Vice President at Norman, Craig and Kummel and Senior Vice President at Lennen & Newell, where he began his career in the mailroom and served in positions ranging from television producer to assistant to the president.

Born in New York, Leo served with the U.S. Marine Corps in World War II. A graduate of Columbia University, he earlier spent two years at the Career Diplomat School of the University of Geneva and the University of Mexico, studying international relations and foreign trade.