Trump has expressed his frustration over Stone's case in the past, calling his sentencing in February an "abomination of justice."
"Roger was a victim of a corrupt and illegal Witch Hunt, one which will go down as the greatest political crime in history," Trump said Thursday. "He can sleep well at night!"
The Justice Department indicted Stone on charges relating to special counsel Robert Mueller's investigation into Russian interference in the 2016 election. While the president has supported Stone throughout court proceedings, his remarks represent a change from his previous comments indicating his intentions of letting the "process play out."