Mr Durst is only charged with killing Berman, but prosecutors allege he also murdered his wife and a Texas neighbour while hiding from law enforcement in 2001.
Mr Durst has admitted to killing his neighbour and dismembering the body but argued self-defence and was acquitted.
After the conviction, Deputy District Attorney John Lewin, called Durst a “narcissistic psychopath” who “killed his wife and … had to keep killing to cover it up.”
And he added: “He’s 78 years old. He’s been walking around for a long time. He had a lot more of a life, you know, Kathie didn’t make 30. On balance, considering what he’s done, he got a lot more of a life than he was entitled to.”
At the sentencing hearing lawyers for Mr Durst filed a motion for a new trial, which the judge denied.
Mr Durst’s lawyers said that they intended to appeal but Durst himself rejected an opportunity to speak to the court.
“SB was an extraordinary human being, I wish I could have known her,” said Judge Windham as he passed sentence.
“I feel I got to know her vicariously far too late and in terrible circumstances. Killing her was a terrible loss to our community and this is a horrific crime it was a witness killing and the circumstances of that crime was the denial of justice to the McCormack family.
“The killing of sb closed any change of vindication. That circumstance is a special circumstance and in this case was a tremendously aggravated and awful, disturbing crime.”