ZURICH—Unshaven, shirt open, a khaki-colored Band-Aid fitted below his right eye, Sepp Blatter leaned forward in his pink upholstered armchair. Just one day after receiving an eight-year ban from FIFA, he made a statement many in the world have been waiting to hear.

“I’ve finished my work in football,” he said.

Though Blatter, 79 years old, plans to appeal the ban imposed by FIFA’s ethics committee and says he had no knowledge of wrongdoing inside FIFA and its member confederations, he has clearly entered the valedictory stage of his long reign over global football, which began in 1998 when he assumed the FIFA presidency. In an interview with The Wall Street Journal at the Dolder Waldhaus hotel in the hills above Zurich, a four-minute drive from FIFA headquarters, Blatter made light of some matters, at one point likening his body to a Ferrari that has been treated like a Citroën 2CV, while at other times becoming defiant, calling his ban “nonsense.”

Blatter also pulled the curtains back on the realpolitik inside FIFA, offering new details on his decision to suspend the former FIFA general secretary Jérôme Valcke and the surprising U-turn that led his former heir apparent, Michel Platini, to throw his support behind Qatar’s bid to host the 2022 World Cup. Shortly before changing his vote, Blatter said, Platini told him: “ ‘Careful. If we vote for Qatar, the next day everyone will say that FIFA sold itself out.’ He told me that,” Blatter added. “And then a week later, he says something changed.”

Blatter believes Platini changed his mind about Qatar during a 2010 lunch at the Elysée Palace between Platini, then-French President Nicolas Sarkozy, and a member of the Qatari royal family in which Sarkozy instructed Platini to support Qatar. France and Qatar share significant business interests in the aerospace industry. “Since I’ve been at FIFA, the World Cup has always been allocated on the recommendation—to not say more—of governments,” Blatter said.