At 19, Mark DeFriest was sentenced to four years in prison after stealing some tools.

That was in 1980. He’s been behind bars since — mostly.

Mr. DeFriest’s initial crime in Florida was arguably a misunderstanding. He took tools that his deceased father had bequeathed to him before his father’s will had been legally processed.

Since then, Mr. DeFriest, now 55, has remained a prisoner because of his 13 escape attempts, seven of them successful, earning him the nickname “Prison Houdini” and more than 30 additional years of incarceration.

On Wednesday, Mr. DeFriest had a chance to gain his freedom legally during a parole hearing in Florida. Instead, the parole commission gave him six more months, with an effective release date in August, so that he can complete a transitional program that teaches life skills, Mr. DeFriest’s lawyer said.