Prosecutors said Jackie Selebi, formerly a leading anti-apartheid activist and well-connected in the ruling African National Congress (ANC) party, had links to organized crime and received about 1.2 million rand ($155,200) to ignore drug trafficking.
Judge Meyer Joffe said he found Selebi, a former Interpol president and an ally of former South African President Thabo Mbeki, guilty of corruption.
Selebi only smirked when asked for comment after the judgment and told Reuters he had "absolutely nothing" to say about the verdict.
The judge said prosecutors had proven during the trial that Selebi had received at least 120,000 rand from Glenn Agliotti — a convicted drug trafficker who was one of the main prosecution witnesses.
The judge said sentencing would take place on July 14-15.
Joffe found Selebi not guilty of defeating the ends of justice but said he found the former national commissioner of the South African Police Service (SAPS) not a credible witness.
"It is never pleasant to make an adverse credibility finding against a witness. It stigmatises the witness as a liar, a person of low moral fibre. It is a stigma that remains forever. It is so much more unpleasant to make such a finding against the person (formerly) at the head of SAPS," Joffe said.
NO MAJOR IMPACT ON ZUMA
Analysts said the verdict would not have a major impact on President Jacob Zuma.
"Basically said, there are no political ramifications, since the case has dragged on for so long, and the links between Zuma and Selebi are sufficiently distant and obscure," said Nel Marais, political analyst at Executive Research Associates.
The guilty verdict on someone who previously held the post of the country's top policeman also had positive implications.
"Given that the country does have a growing corruption problem, it is a positive development that our courts and our prosecutors have the courage to convict someone so senior," said Gary van Staden, political analyst with independent economists NKC.
Selebi was suspended as national police head in January 2008. Critics of former President Mbeki — who stepped down as the country's leader under pressure from the ruling party in September 2008 — accused him of protecting Selebi.
Selebi argued during the trial that he had been the victim of a conspiracy but Judge Joffe dismissed this on Friday, saying there was no political conspiracy to prosecute the former police chief.
