Dentsu Inc. decided Thursday to promote Senior Vice President Toshihiro Yamamoto to president, replacing Tadashi Ishii who will step down to take responsibility for the overwork-related suicide of a young employee.

Under the leadership of 58-year-old Yamamoto, effective Monday, Japan's top advertising agency faces the task of regaining trust by reforming the work environment that led to the death of 24-year-old Matsuri Takahashi in December 2015.

"My mission is to re-establish trust in Dentsu in Japan, and build a sustainable growth path for the long term," Yamamoto said in a statement, calling reform of the working environment "the top priority."