It is Mulvey's first job in football since he was sensationally removed from Roar's head coaching role just months after guiding the team to the A-League championship.
Mulvey, 52, was sacked due to a supposed disagreement between himself and Brisbane over the club's footballing philosophy.
He has maintained a dignified silence ever since but now has the chance to preach his own philosophy in Malaysia.
Sabah, also known as the Rhinos, is the former club of several Australian ex-players and coaches, including Scott Ollerenshaw, Gary Phillips and Mulvey's former Roar assistant Ron Smith.