FRANKFURT — Ferdinand Piëch, the Porsche family scion who has dominated Volkswagen for more than two decades, will resign as chairman of the automaker’s supervisory board, the company said on Saturday, in what appeared to be a stunning defeat for a manager used to getting his way.

Mr. Piëch, a 78-year-old Austrian, recently sought to force out Martin Winterkorn, a onetime protégé, as Volkswagen’s chief executive. But the move backfired after Mr. Winterkorn refused to go and other members of the supervisory board rallied behind him.

Volkswagen said in statement on Saturday that “the mutual trust necessary for successful cooperation no longer exists” on the supervisory board. As a result, Mr. Piëch will give up his post as chairman, effective immediately. Ursula Piëch, his wife, will also give up her seat on the board, Volkswagen said.

Berthold Huber, a labor leader who is deputy chairman of the supervisory board, will serve as acting chairman until a new chairman is chosen, Volkswagen said. In Germany, the supervisory board oversees the work of the management board, which is in charge of day-to-day operations.