Bernard Tyson, Kaiser Permanente CEO and Chairman, passed away unexpectedly in his sleep on Sunday night, the health care giant announced in a press release.

Tyson, who has served as chairman since 2014, was 60 years old.

"An outstanding leader, visionary and champion for high-quality, affordable health care for all Americans, Bernard was a tireless advocate for Kaiser Permanente, our members and the communities we serve," a Kaiser press release reads. "Most importantly, Bernard was a devoted husband, father and friend. We all will miss his tremendous presence in our lives."

Tyson, who was born and raised in the Bay Area, received his bachelor’s degree in Health Service Management from Golden Gate University in San Francisco. He worked at Kaiser for more than 30 years, rising up the ranks to company chairman.

Executive Vice President and Group President Gregory A. Adams has been named interim CEO and Chairman, effective immediately.

“Bernard was an exceptional colleague, a passionate leader, and an honorable man. We will greatly miss him,” said board member Edward Pei, Chair of the Executive Committee and the Governance, Accountability and Nominating Committee. “The board has full confidence in Greg Adams’ ability to lead Kaiser Permanente through this unexpected transition.”