Haruno Yoshida, co-chair of Women 20 (W20), a Group of 20 engagement group, died June 30 from heart failure, the W20 Japan committee announced Monday. She was 55.

Yoshida was the first woman to serve as vice chair of the Board of Councilors at Keidanren, the powerful business lobby also known as the Japan Business Federation.

She was a longtime proponent of improving workplace diversity and was featured regularly in international forums as a role model for working women.

Yoshida was known as a leading business figure who worked tirelessly to bridge the gender divide in a country known for its low gender equality.

In 2012, she became the first female president of BT Japan Corp. following stints at Motorola Mobility LLC, Verizon and NTT Communications Corp.

In 2015, she was appointed as a vice chair of the board at Keidanren, where she also chaired the committee on gender diversity until 2018.

Yoshida pushed for better gender parity in the realm of politics as well, and was appointed in 2016 to the Council for Regulatory Reform, a committee that advises the Cabinet Office on economic and social policy.

At the time of her death, she was serving as an adviser to Keidanren and co-chair of W20.

A Keio University graduate and an alumnus of Imperial College London, she was featured in Fortune magazine's World's 50 Greatest Leaders List 2017.