McCusker's two-year tenure is effective immediately.
Serving executive committee member Spencer Wong, MD and chief creative officer at McCann Worldgroup Hong Kong, has also taken up the role of vice-chairman with the support of a committee comprising of DDB's Simone Tam, Ogilvy's Adam O'Conor and JWT's Desmond So.
"We are witnessing a resurgence in creativity in Hong Kong, evidenced by our industry's strong performance at prestigious award shows such as Cannes," McCusker commented.
"I look forward to working with all the 4As members to continue in the dynamic path that ex-chairman Richard Thomas and the previous excomm embarked upon: to build upon our position as a hub with creativity at its core and a gateway for brands to move onto the international stage."
23 full members and 19 affiliated members (who are principle representatives of the 4A agencies) of the HK4As has casted their votes supporting McCusker's appointment.
Elections for the various HK4As sub-committees is underway and will also be announced shortly.
The HK4As AGM will be held at Butterfield's Quarry Bay on 18 February 2011 at 5pm.