"I'm looking forward to working alongside Dougie, who I have known for many years," Lawrence told the Palace website.
Co-chairman Steve Parish said: "He was Dougie's selection, someone he very much had in mind when he agreed to take the job."
He added: "I think he's the right person to work with Dougie, nurture him and point him in the right direction on things."
Palace are struggling at the foot of the table and will hope Lawrence's experience will make them safe.