Mark Milligan captained the U/23 squad for the 2006 Peace Cup in Vietnam. His abilities drew the attention of Guus Hiddink who chose Milligan as a substitute for the 2006 World Cup. Although he did not play any World Cup games, it was clear Milligan had talent and leadership beyond his years. Milligan was a leader for the 2008 Olympic Games campaign. The competitive defender led the Australians to an 11th place finish in Beijing.