During a seven-day trial at Leicester Crown Court, Thomas Dunkley, 29, admitted cutting up the ex-boxer's body with a chainsaw and storing his body in freezers at Cummins' bungalow.
He denied murder and claimed he had panicked after Cummins died of natural causes in his sleep.
A jury of seven women and five men took just under eight hours to find him guilty of murder.
He was found guilty of murder by a majority verdict of 11-1.
A man has been found guilty of the murder of a former champion boxer who was found dismembered in freezers at his home.
The jury in the trial of a man acccused of killing a former boxer and chopping up his body has seen pictures of him buying a chainsaw.