The Seattle-based savings & loan said independent director Stephen Frank would become chairman of the board on July 1. Killinger, who has presided over WaMu amid a plunging stock price and earnings, will remain CEO.
Frank, 66, has been a director since 1997 and is the retired CEO of utility company Southern California Edison, a subsidiary of Edison International.
WaMu said in April that it would consider splitting the CEO and chairman roles at a future board meeting. Angry stockholders have agitated for management changes at the bank, whose shares have plunged 79 percent during the past year.
The board shake-up comes the same day Wachovia said it had ousted Ken Thompson as CEO after a host of troubles and an ill-timed takeover of a big mortgage lender dragged down its earnings and its stock.
Last month Wachovia , the fourth-largest U.S. bank, split its CEO and chairman roles. On Monday Lanty Smith, who replaced Thompson as chairman, was named interim CEO.
Charlotte, North Carolina-based Wachovia said Thompson, who had run the company since April 2000, was retiring at the request of its board.
Killinger and Thompson join a growing list of banking chiefs whose careers were derailed by the global credit crisis that began last summer. Citigroup Inc's Charles Prince and Merrill Lynch & Co.'s Stanley O'Neal also were forced out by their boards.
Also on Monday, Washington Mutual revised its rules so that director nominees must receive a majority of votes cast in uncontested elections. It also changed the leadership of key board committees and announced a search for new independent directors.
Shares of Washington Mutual fell 12 cents, or 1.3 percent, to $8.90 in morning New York Stock Exchange trade.