Muscat has been working assiduously behind the scenes for several months to convince the Socceroos utility to return for a second spell at the club he left in 2015 to join UAE side Baniyas.
But his chase for Milligan, who turns 32 on Friday, was complicated by the player's desire to test himself in England, where Championship club Bolton Wanderers made a firm offer before work permit issues shut the door on him earlier this month.
While Milligan has always been a vocal advocate of the A-League, he was bitterly disappointed to be denied the chance to play in England, especially after failing to convince Victory to release him to join Crystal Palace back in 2013.
But a salary of around $800,000 for the looming A-League season will make it a soft landing for Milligan, as he heads back to the club he made 74 appearances for across three seasons whilst scoring 11 goals.
A Joe Marston medalist for Victory in 2015, Milligan showed he had lost none of his potency at last month's FIFA Confederations Cup in Russia, where he skippered Australia twice.
His arrival, just days after fellow Socceroo James Troisi returned to the club in a major transfer twist, shows how serious Muscat is in wresting the A-League crown from Sydney FC's grasp this season.