Mr Preston will succeed Jeh Johnson, who stepped down as Defense Department general counsel in December, reports Executive Gov.
Before joining the CIA in 2009, Mr Preston was a partner at US firm WilmerHale where he was the co-chairman of the firm’s defence and national security practice.

Distinguished service

In an email to agency employees, CIA Director John Brennan highlighted that Mr Preston was awarded the Distinguished Intelligence Medal and the National Intelligence Distinguished Service Medal last year in recognition of his efforts during the run-up to the operation in which Osama Bin Laden was brought to justice.
Mr Preston also served as deputy assistant attorney general from 1995 to 1998.