Robertson signed with Burnley in 1997 after being noticed playing for Australia at the 1997 FIFA World Youth Championship.

[2] In December 2007, Robertson signed with Sydney FC as cover for Adam Casey, out with a long-term injury.

[3] Robertson played one full international match for Australia in 2001.

His father, Alex, had emigrated from Scotland to play for Sydney City in the National Soccer League and eventually represented Australia eight times in non-official matches.

[4][5][6] Robertson's son Alexander, who was born in Scotland whilst he played for Dundee, currently plays for Cardiff City and the Australian national football team.