The 62-year-old, one of the most powerful figures in German football, was charged with dodging 3.5 million euro (£2.9 million) in taxes through an undeclared Swiss bank account.
But when his trial opened on Monday, he admitted to avoiding 15 million euro (£12.5 million) more. Then it came out through an examination of documents he provided to investigators shortly before the trial that he owed 27.2 million euro (£22.7 million) in total.
German news agency dpa reported that prosecutors had demanded a five-and-a-half-year prison term, while his defence team was looking for a suspension of sentence on probation, arguing that he had turned himself in for tax evasion and provided details to the court.
Following the verdict, defence lawyer Hanns Feigen said he would appeal against the decision to see how a higher court would value Hoeness's "not ideal" confession.
He added that he was convinced the appeals court would come to a "better result" than the Munich state court did.
Hoeness will remain free on bail pending the outcome of the appeal.
German authorities have been cracking down on tax evaders in recent years, and have recovered hundreds of millions of euro.
Their widely-publicised purchase of leaked account information on thousands of investors, as well as high-profile cases such as that against Hoeness and former Deutsche Post AG chief Klaus Zumwinkel, has led to thousands of people turning themselves in.
Hoeness, who is also part owner of a Nuremberg sausage factory, reported himself to the tax authorities last April - around the same time that German media were investigating reports of high-profile tax evaders.
News of the case against the national icon prompted even Chancellor Angela Merkel's spokesman to weigh in and say the country's leader was disappointed in him.
As a player, Hoeness was a Bayern star who won the 1972 European Championship and the 1974 World Cup with West Germany, and three straight European Cups - the predecessor of the Champions League - before retiring in 1979 with chronic knee problems.
He became the Bundesliga's youngest coach when he was 27.
Bayern has been enjoying unprecedented success under Hoeness's presidency. The club stood by him during the investigation, and its supervisory board is expected to meet following the verdict to see what steps to take next.
Bayern Munich said it would issue a statement later today.