"As our business continues to grow, there was a clear case to diversify our leadership at the executive level," said chief executive David Tudehope.
"William's years of international experience in this space, coupled with extensive market knowledge and management skills, make him the ideal candidate for this role.
"William has already proved himself a great asset to the company and I look forward to his continued success."
He brings international experience to Macquarie Telecom, hHaving lived and worked in the UK, USA, France, Switzerland, Africa and Pakistan,.
Commenting on the appointment, Priest said, “I am delighted to be appointed to this role and to join Macquarie Telecom, a company that recognises the importance of delivering excellence in customer service."