By Pete Schroeder WASHINGTON (Reuters) - The U.S. Senate voted on Thursday to confirm former banker Jelena McWilliams to serve as chair of the Federal Deposit Insurance Corporation (FDIC), completing President Donald Trump's team of key banking regulators. Her appointment nearly 18 months into Trump's administration will allow financial regulators to accelerate efforts to fulfill his pledge to scale back rules introduced following the 2007-2009 global financial crisis. McWilliams takes over from Martin Gruenberg, an appointee of President Barack Obama. Gruenberg has been a vocal defender of post-crisis rules and has resisted efforts by Trump's other agency heads to weaken them. The FDIC serves as a key regulator for many of the nation's banks and is the overseer of the country's deposit insurance program. The watchdog plays a critical role in overseeing several joint-agency regulations, including capital requirements and the "Volcker Rule" banning proprietary trading. McWilliams, who had been the top attorney for Fifth Third Bancorp, was nominated to the post by Trump in November. (Reporting by Pete Schroeder; editing by Michelle Price and Bill Berkrot)