SACRAMENTO, Calif. (AP) — Nancy McFadden, the chief of staff to California Gov. Jerry Brown and the driving force behind many of his key initiatives, died Thursday in her home after a long battle with ovarian cancer. She was 59.

“Nancy was the best chief of staff a governor could ever ask for. She understood government and politics, she could manage, she was a diplomat and she was fearless,” Brown said in a statement.

McFadden was hired as Brown’s chief of staff in 2011, when he returned to the governor’s office, and became a leading adviser on everything from criminal justice reform to climate policy. She was often the chief negotiator between Brown’s office and lawmakers, particularly on an extension of California’s cap-and-trade climate legislation that passed last year after months of tense dealings with legislators and interest groups.

“She was the fulcrum of the administration — a one-woman mission control center for every major effort and everything of consequence that was achieved over the past seven years,” Steven Maviglio, a friend and Sacramento political strategist, wrote.

McFadden’s high-profile political work began long before joined the Brown administration.

She served as deputy associate attorney general in the Clinton administration, then as deputy chief of staff to Vice President Al Gore. She was also general counsel for the U.S. Department of Transportation.

Friends and co-workers described McFadden as someone who, despite her commanding influence, was always willing to share credit with those around her on policy achievements in the Brown administration.

McFadden stepped away from the Capitol in January to focus on her health. She had beaten her first diagnosis of ovarian cancer but it returned four years ago. She planned to stay fully engaged with the job from home.

“I am grateful to the governor, Anne and Team Brown for their support and look forward to building on what we’ve already accomplished in the year ahead,” she said in a statement at the time.