Kathleen Kane, was found guilty of all nine counts including conspiracy, official oppression and perjury.
Perjury, which is a serious charge, can alone carry a penalty of seven years in prison.
Her licence to practise law has been suspended and has she resigned as attorney general.
Kane, 50, is due to be sentenced within 90 days, and has vowed to appeal.
"I have been honoured to serve the people of Pennsylvania and I wish them health and safety in all their days," Kane said in a statement.
She was found guilty of leaking sealed court documents intended to embarrass a rival prosecutor, Frank Fina, who Kane believed had planted a news story claiming that she had ended a statehouse sting operation.
An aide for Kane testified during the trial that she became "hell-bent on getting back at Frank Fina", and described her behaviour as "unhinged".
She instructed her aides to leak the information the news media, and later lied under oath when questioned by state officials.
During the trial, Kane declined to testify, and her defence team did not call a single witness to the stand.
She claims to be the victim of an "old-boys" network that are taking revenge on her for revealing lewd messages sent by government employees using state email servers.
Those embarrassing emails led to the resignation of two state Supreme Court justices, and other top government employees.
"What she did while she was the attorney general, the fact she would commit criminal acts while the top prosecutor, is a disgrace,'' assistant district attorney Michelle Henry said after the verdict.
The judge has released Kane on bail after requiring her to forfeit her passport to prevent her from leaving the country.
Before being released the judge also warned Kane that there would be additional consequences if there were any signs that she was retaliating against witnesses.
Several of her top aides testified against her during the trial in exchange for immunity.
Kane, once a rising star of the Democratic Party, assumed office in 2013 becoming the first woman, and the first Democrat, to hold the position of attorney general.
She had not held an elected position before then.
She now faces a maximum sentence of 28 years in prison, however a lesser sentence is expected.
The top law enforcement official in the US state of Pennsylvania has been convicted of several crimes after she leaked documents critical of a rival.