President Ronald Reagan’s final chief of staff, Kenneth M. Duberstein has passed away.

The Washington Examiner reports:

Duberstein had been ill and retired from his advocacy firm, The Duberstein Group, Duberstein’s wife Jackie told Axios. He died at Sibley Memorial Hospital on Wednesday. Jackie did not reveal the cause of death.

Duberstein served in an assortment of business and White House roles during his career. He held several smaller roles in the White House before becoming deputy chief of staff in 1987. He was later promoted to chief of staff in 1988, where he served in the role until the end of the Reagan administration.

Duberstein served on several corporate boards after his time in the White House, including Boeing and the Brookings Institution. He had been the longest-serving lead director on Boeing’s board. He also was a consultant on Aaron Sorkin’s TV show The West Wing.

The former chief of staff shifted away from Reagan-esque politics in 2008 when he announced his support for then-presidential candidate Barack Obama. He also filed a brief supporting gay marriage in the 2013 Supreme Court case of Hollingsworth v. Perry.