Gary Peel was found guilty on four counts of obstruction of justice, bankruptcy fraud and possession of child pornography by a federal jury in East St. Louis Friday afternoon.
Peel left the courtroom visibly shaken with his wife by his side. He declined to comment.
He is released on bond pursuant to his arraignment.
On Wednesday there will be a hearing to decide if Peel will be taken into custody pending sentencing.
He faces up to 35 years in prison.
Gary Peel was prosecuted for blackmailing his ex-wife Deborah Peel with nude photos taken of her 16-year-old sister in 1974.
He and Deborah Peel were married in 1967 and divorced in 2003. During contentious settlement proceedings Gary Peel filed for bankruptcy in 2004.
During the trial Assistant U.S. Attorney Kevin Burke told jurors that Peel threatened to bankrupt his ex-wife in legal fees if she did not stop trying to get a deposition of his current wife, Deborah A. Pontious-Peel.
He told the jury that Peel planned to send the nude photos to Deborah Peel's parents if she did not agree to a new divorce settlement.
After the trial Deborah Peel said, "I'm glad it's over. You never know what a jury will do."
She said the ordeal has cost her financially and emotionally.
Donna Rodgers, Deborah Peel's younger sister and subject of the photos, also said she was glad the trial was over.
"My sister is my hero," she said.
When she found out the photographs she thought had been destroyed more than 30 years ago still existed, Rodgers said she was shocked.
She was angry that Gary Peel would try to hurt her parents who treated him a like a son.
"Our parents treated him like a son. Our parents trusted him like a son," Rodgers said.
Gary Peel's daughter Jennifer Cullen said it was upsetting to see her father in the situation and had mixed emotions about the trial's outcome.
Acting U.S. Attorney Randy Massey said he was pleased with Burke's performance and that of Assistant U.S. Attorney Jennifer Hudson. He said he had been confident of the trial's outcome.
"When the government brought this case to the grand jury there was sufficient evidence to get a guilty conviction," he said.