Agustin Pichot has resigned from his role on the World Rugby Council after his defeat by Sir Bill Beaumont in the election for World Rugby chairman.
Ex-England captain Beaumont was re-elected for another four years on 2 May after beating former Argentina skipper Pichot by 28 votes to 23.
Pichot, 45, had served as Beaumont's vice-chairman for the past four years.
He has resigned as Americas Rugby president and the Argentine Rugby Union representative on the council.
"The only reason I have been a part of World Rugby to this day, and which in turn is the same one that has moved me to run for president, is the conviction that World Rugby needs change," said Pichot.
"But my proposal, which I fervently believe in, has not been chosen, and that is why I choose to step aside.
"I cannot conceive of occupying a place just for the sake of occupying it."
Pichot won the support of the Sanzaar nations (South Africa, New Zealand, Australia and Argentina) as well as South America and Asia in his election bid.
French Rugby president Bernard Laporte was elected vice-chairman under Beaumont.