Tadashi Ishii joined Dentsu in April 1973. After holding several senior positions in the Account Management and International Management Divisions, in 2002 he was appointed executive officer, and in 2004, senior executive officer. He became managing director and joined the Dentsu board of directors in 2006. He was appointed president & CEO of Dentsu Inc. in April 2011.
Ishii holds a degree in Faculty of Foreign Studies from Sophia University, Tokyo.
Established in 1961, Dentsu is Japan's largest communication firm and one of the largest network agencies in the world. Dentsu PR is a wholly owned subsidiary of Dentsu Inc and is headquartered in Tokyo.