John G. Stumpf’s departure from Wells Fargo was inevitable, but it came quickly.

The Wells Fargo chairman and chief executive’s “retirement,” announced Wednesday evening, clears the way for his successor to fix the culture that led to millions of fake accounts being opened. Along with the $228 billion lender’s board, though, his successor, Timothy J. Sloan, has to show he can break with the past.

The last stage of Mr. Stumpf’s fall from grace must have come faster than anyone, including Wells Fargo’s stodgy board, had expected. Only two days earlier, the bank announced new executive appointments that bolstered its operating committee and Mr. Sloan’s responsibilities. Now the latter part of that, at least, has been overtaken by events.

Mr. Stumpf’s final chapter began when his California-based bank agreed in early September to pay $185 million to settle allegations that its bankers illegally opened accounts to help meet sales targets. Complacency and prevarications at two disastrous appearances before Congress – with his belated forfeiture of $41 million in unvested stock awards – undid the good work that made Wells Fargo unusually solid among big American banks during and after the 2008 mortgage crisis.