"Trevor's contribution has been wonderful since he joined the Board," Brayshaw said.
"We regretfully accept his resignation and wish to pay tribute to his leadership, guidance and advice especially with the direction he took to help enable us to play two games in Hobart from this year onwards."
O'Hoy will be replaced by Brady Scanlon, an executive director of Taverners Group.
"Brady has worked with the Taverners Group for more than 15-years here and overseas," Brayshaw explained.
“The Scanlon name is very dear to the North Melbourne Football Club with Peter Scanlon one of our biggest supporters and most loyal friends. We owe a lot to the Scanlon family and having Brady as an official Board member will significantly enhance our capabilities as an organisation.”
Currently responsible for the Health portfolio within the Taverners Group, Brady Scanlon he is also a member of its investment committee.
"Trevor is a big loss there's no doubt, but replacing him with someone of Brady's experience and ability is a massive coup for our club.
"We are pleased however, that Trevor has expressed a desire to remain in close contact with the Board, staff and players and provide us with ongoing support."