However, Jonathan did not give details of his anti-corruption fight, saying several cases are still pending in court.
Jonathan said he reformed the anti-corruption agencies in the country to enhance their capacity to function effectively.
"We reformed the institutions and introduced various mechanisms to stop the corruption problems in our country without publicity," he said.
He stated this while speaking to students at the Oxford Union of the University of Oxford, United Kingdom, on the theme "Promoting Youth Entrepreneurship."
The former president, however, did not expatiate on his anti-corruption fight.
He told the students, who inquired about the anti-corruption war under his government, that he did not want to "interfere with the legal processes" because "several matters are pending in court."
Jonathan, who lost his 2015 re-election bid, is believed to be making reference to the ongoing anti-corruption war under President Muhammadu Buhari, in which arrests and prosecutions of allegedly corrupt persons dominate media contents.
Many, especially the opposition, have criticised Buhari's corruption fight, saying it is vindictive and without regard to the rule of law.