Former Fifa executive Chuck Blazer agreed to go “undercover” to help the US government expose widespread corruption across world football in order to avoid spending the rest of his life in prison, according to details of his plea bargain made public on Monday.

Blazer, 70, pleaded guilty to 10 charges, including bribery, money laundering and tax evasion, in 2013. The charges carried a maximum concurrent imprisonment term of 75 years, but Blazer agreed to become an informant for the FBI and US justice department – and collect evidence implicating other Fifa executives – in return for immunity from prosecution.

The plea bargain agreement reveals that Blazer, who was general secretary of the North and Central American Concacaf governing body, began providing information to the authorities in December 2011 – more than three years before the US government charged 14 current and former Fifa officials with “hijacking” international football to run “a World Cup of fraud” to line their pockets by $150m.

Blazer, who was a Fifa executive committee member from 1997 to 2013, secretly pleaded guilty in November 2013 in a closed Brooklyn courtroom. According to his plea bargain, which was redacted in parts, Blazer admitted that he, along with other Fifa officials, accepted bribes for voting for South Africa’s bid for the 2010 World Cup and a bribe related to the 1998 World Cup in France.

“I and others on the Fifa executive committee agreed to accept bribes in conjunction with the selection of South Africa as the host nation for the 2010 World Cup,” he told the judge in the secret court session in November 2013.

He told the judge his involvement in the acceptance of bribes in connection with the South African bid began “in or around 2004 and continuing through 2011”. In a nod to a wider top-level conspiracy at Fifa, Blazer added: “My actions described above had common participants and results.”

South Africa won the right to stage the 2010 World Cup in 2004, after missing out on the 2006 tournament to Germany in controversial circumstances.

Blazer also admitted to accepting bribes related to five Concacaf Gold Cup tournaments between 1996 and 2003.

In exchange for avoiding jail time, Blazer agreed to “provide truthful, complete and accurate information” to prosecutors and to “participate in undercover activities pursuant to the specific instructions of law enforcement agents”. Blazer also agreed to testify at future trials of his former Fifa colleagues and pay back more than $11m in taxes he avoided.

The fallout from the US investigation into Fifa has led to an unprecedented crisis for the governance of world football, forcing the dramatic resignation of Fifa’s longtime president, Sepp Blatter.