He is a convicted felon because the jury convicted him of a felony. Once the guilty verdict is handed down, the defendant is convicted and no longer has the presumption of innocence.

In law, a conviction is the determination by a court of law that a defendant is guilty of a crime. A conviction may follow a guilty plea that is accepted by the court, a jury trial in which a verdict of guilty is delivered, or a trial by judge in which the defendant is found guilty.

It's not defamation to call him a convicted felon because the conviction has not been overturned.