January 12, 2017
Mr Giuliani, once a leading contender for secretary of state, said Mr Trump would meet the team on a regular basis.
He was selected because of his private sector cybersecurity expertise, a Trump transition team statement said.
Mr Trump has said he plans to create a cybersecurity team within his first 90 days in office.
Mr Giuliani’s appointment follows Russian hackers’ apparent attempt to meddle in November’s US election.
Mr Trump accepted for the first time at a press conference on Wednesday that the Russians were behind the cyber-breach.
Thursday’s announcement from the president-elect called cyber-intrusion “the fastest growing crime in the United States and much of the world” and said it was a “major threat” to national security.
But it stopped short of giving a formal title to Mr Giuliani, 72, who runs an international security consulting firm.
A vocal Trump supporter during the campaign, he last month said he was taking himself out of the running for a cabinet job after his business dealings came under media scrutiny.