He told the Home Affairs Select Committee that police tasked with protecting high-profile individuals like Harry, 27, cannot cross “the golden line” by getting involved in their personal life.
Mr Hogan-Howe was quizzed by committee chairman Keith Vaz about the snaps of Harry naked in a hotel room.
“We’re already reviewing that particular incident. Our role is to maintain the security of our protected individual,” he said.
“They have to lead a normal life and we have to strike a balance between intrusion into their life and keeping them safe.
“There is a golden line that cannot be crossed, which is getting involved in the social lives of the principals.
“There was nothing inappropriate and what appeared in photographs to be wrong was not as appeared,” he added.