Chung Mong-joon made the criticism in a memoir published in South Korea last week, titled "My Challenge, My Enthusiasm." Chung had been regarded as a candidate to succeed Blatter as FIFA president before being defeated for re-election this year in a vote by Asia's governing body.
The book reached stores as Blatter prepared to present detailed anti-corruption reforms in October after a year of scandal.
"President Blatter is fluent in five languages, has a good way with words and is intelligent ... but I think he is not an international gentleman and he is like a little brat," Chung said in the book.
Chung, who served as a FIFA vice president for 16 years, accused Blatter of trying to usurp the authority of FIFA's executive committee with his proposal to create an oversight, anti-corruption panel that could include former U.S. Secretary of State Henry Kissinger and opera singer Placido Domingo.
"(The FIFA) executive committee is an independent organ aimed at performing the roles of 'checks and balance' to prevent the president from going beyond his own authority. Blatter is now attempting to take away the power of the executive committee and neutralize any effort to check his power," Chung wrote. "It's a similar scheme that so many dictators have used in world history."
Chung also said that Blatter had unsuccessfully made a series of unrealistic proposals, such as holding the World Cup every two years rather than every four and moving the goalposts to help allow more scores.
"Those proposals ... only triggered unnecessary friction and confusion," he wrote.
FIFA said Monday it would not comment on Chung's memoir.
Blatter has long been a magnet for criticism, but the 75-year-old was elected unopposed this year to a fourth term as FIFA president. His only challenger, Mohamed bin Hammam, withdrew on the eve of the vote amid allegations that he tried to bribe Caribbean voters in his campaign to unseat Blatter. Bin Hammam has denied the charges.
FIFA Vice President Jack Warner, and two other FIFA executive members, Amos Adamu and Reynald Temarii, were suspended after allegations of corruption. Warner then resigned.
Blatter told The Associated Press late last month he will announce his reform agenda after an executive committee meeting Oct. 20-21.
Last month, European Club Association Chairman Karl-Heinz Rummenigge called on Blatter to introduce reforms in FIFA or risk the fate of toppled Egyptian President Hosni Mubarak. Blatter later said he had made peace with Rummenigge.
Chung, a senior South Korean lawmaker and billionaire businessman, had long headed the country's soccer association and was a key factor in helping South Korea land the right to co-host the 2002 World Cup with Japan. He is contemplating a run for South Korean president next year.
Chung's late father, Chung Ju-yung, founded the Hyundai conglomerate — a top-tier FIFA sponsor — and ran unsuccessfully for president of South Korea in 1992. The younger Chung was also a national presidential candidate in 2002.