Chuck Blazer in 2005. He was central to the rise of the sport in the United States. (Reuters)

The charade only ended in the final years of Chuck Blazer’s life. Stripped of his extravagances, soccer’s gregarious and greedy dealmaker was forced to admit to his years of corruption and confined to a New Jersey hospital.

The eccentric bon vivant, who once strode across the global stage being flattered by sport and political leaders, died in disgrace July 12 at 72.

However much Mr. Blazer elevated the status and wealth of soccer in North America over several decades, any achievements were polluted by the ravenous appetite of “Mr. 10 Percent” to seek bribes and siphon cash from deals into his personal account.

Mr. Blazer went on to play a central role in exposing soccer’s fraudulent culture, which led to FIFA President Sepp Blatter, longtime leader of soccer’s governing body, being toppled. But he turned only when presented with little option but to become a cooperating witness.

The impact of Mr. Blazer’s death on the FIFA prosecution in the United States — where three South American soccer officials are set to go on trial in November — is unclear. Many of the more prominent figures who might have faced him as a star government witness have already pleaded guilty.

FIFA President Sepp Blatter and Mr. Blazer, who turned over evidence of corruption that led to Blatter’s resignation in 2015. (Fabrice Coffrini/Agence France-Presse via Getty Images)

Mr. Blazer was driving his mobility scooter on a Manhattan street in 2011 when he was stopped by U.S. government agents and threatened with arrest. He had failed to fill in tax returns for years, and soon became a government informant, using his role on FIFA’s already-tainted executive committee to secretly record conversations with associates.

He swept up evidence that formed the foundations of a Justice Department case against world soccer executives who embezzled cash from commercial contracts and sought payments in return for backing countries as World Cup hosts.

At a November 2013 court hearing where his treatment for rectal cancer, diabetes and coronary artery disease was disclosed, Mr. Blazer entered 10 guilty pleas. He admitted to sharing in a $10 million bribe scheme with others to support South Africa’s bid for the 2010 World Cup, and to facilitating a kickback linked to Morocco’s failed bid for the 1998 World Cup.

His guilty pleas were only unsealed by a New York court in July 2015 after the American investigation into FIFA exploded into public view with a raid on a Zurich hotel ahead of the annual gathering of soccer nations.

Since then, U.S. prosecutors have brought charges against more than 40 soccer officials and associates, while the Swiss attorney general has been conducting parallel investigations.

Charles Gordon Blazer was born in New York on April 26, 1945. A graduate of New York University, he worked as a salesman and started in soccer coaching his son’s club in New Rochelle, N.Y.

He joined boards of local and regional soccer organizations before becoming the U.S. Soccer Federation’s executive vice president in 1984. He helped to form the American Soccer League, a precursor to Major League Soccer, before entering regional soccer politics through CONCACAF, the sport’s governing body for the North and Central American and Caribbean region.

Mr. Blazer urged Jack Warner to run for president of the organization in 1990. When the Trinidadian won, he made Mr. Blazer the general secretary — a position he held until 2011.

In 1991, Mr. Blazer created the CONCACAF Gold Cup, the organization’s national team championship that is played every two years and is now underway. He rose within FIFA to become chairman of its marketing and television advisory board, and then turned on his boss, who also served with him on FIFA’s executive committee.

Corruption had been rumored for years within world soccer before Mr. Blazer provided evidence, accusing Warner and Mohamed bin Hammam of offering $40,000 bribes to voters in the 2011 FIFA presidential election. Bin Hammam, a Qatari who headed the Asian Football Confederation, had been the lone challenger to Blatter, who was elected unopposed to a fourth term after Warner and bin Hammam were suspended.

Blatter was elected to a fifth term in 2015 before resigning after the raids in Zurich.

Mr. Blazer’s conduct was as corrupt as the actions of the people he accused.

He pleaded guilty in November 2013 to one count each of racketeering conspiracy, wire fraud conspiracy, money laundering conspiracy and willful failure to file a Report of Foreign Bank and Financial Accounts, and to six counts of tax evasion.

A separate CONCACAF investigation report released in 2013 said Mr. Blazer “misappropriated CONCACAF funds to finance his personal lifestyle,” causing the organization to “subsidize rent on his residence in the Trump Tower in New York; purchase apartments at the Mondrian, a luxury hotel and residence in Miami; sign purchase agreements and pay down payments on apartments at the Atlantis resort in the Bahamas.”

While Mr. Blazer was banned from soccer by FIFA in 2015, he was awaiting sentencing when he died. His lawyers announced his death but did not provide additional details.

A marriage to Susan Aufox ended in divorce. Survivors include two children and several grandchildren.

There were almost no public tributes from FIFA or CONCACAF immediately after his death. In U.S. Soccer, the only acknowledgment of Mr. Blazer’s passing was a comment in a news conference by men’s national team coach Bruce Arena.

“I’ve known Chuck for a lot of years. He did a lot for the sport. Sorry about all the issues regarding FIFA,” Arena said.

“But he was a good man.”