Former Loaded editor Harbinson is set to join Dennis Publishing in August, taking over from Eoin McSorley, who has filled in as acting editor.
Harbinson said: "It's going to be fun meeting the challenges of this role head on."
He will have to face Maxim's nosediving circulation and the pressure men's monthlies are under from Nuts and Emap's Zoo.
In the first half of this year Maxim's circulation dropped to 185,908, 18.2% down on the 227,377 copies sold during the second half of 2005. It was embarrassingly forced to reduce its ABC figure because of delays to the delivery of 4,530 free copies.
Harbinson has been brought in by Bruce Sandell, the former Maxim publisher who stepped up to become managing director of Dennis's consumer division in March.
"Derek has the vision to drive copy sales and make sure the magazine outperforms the market," Sandell said.
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