BIRMINGHAM, Ala. — The fired head of Alabama’s two-year colleges Roy Johnson formally pleaded guilty Monday to 15 charges in a far-reaching federal investigation of corruption in the state’s two-year college system.

Johnson, 62, has agreed to pay more than $18 million. Federal authorities say the money was proceeds from the criminal activity of Johnson and others.

Also pleading guilty Monday was Joanne Jordan, former interim president of Southern Union State Community College. Jordan, 66, was charged with paying false invoices to contractors and giving Johnson’s family members contracts with the community college. She is also accused of giving false testimony to a grand jury investigating the two-year college system, U.S. Attorney Alice Martin said in a release.

Johnson entered his plea in federal court in Birmingham Monday to 15 charges, including bribery and witness tampering.

Johnson is a once-powerful lawmaker who served as chancellor of the Department of Postsecondary Education for four years until he was fired in 2006. He is also former president of Southern Union Community College, which has campuses in Wadley and Opelika.

U.S. District Judge Karon Bowdre is scheduled to sentence Johnson on Aug. 20.

“Former Chancellor Johnson committed crimes of greed not need and in doing so set a culture of corruption and entitlement into action in the postsecondary system,” Martin said.

The plea agreement between Johnson and federal prosecutors is part of a lengthy investigation into the two-year college system that has also resulted in guilty pleas by one former legislator, while a current lawmaker has been charged and is awaiting trial.

Former state Rep. Bryant Melton, D-Tuscaloosa, resigned in 2006 and pleaded guilty to charges related to his job at Shelton State Community College. State Rep. Sue Schmitz, D-Toney, was arrested last month and has pleaded not guilty to a nine-count federal indictment charging her with mail fraud and theft. She is awaiting trial.