Born on 9th June, 1981, Justin started his career at Floriana F.C. before joining Bulgarian side Dobrudzha on loan in 1998. In 2002, he joined Birkirkara F.C. where he spent 3 years. After, he joined French side US Quevilly in his second spell out of his birth country.

After having a short spell with RE Virton in Belgium, he then returned to Malta to join Marsaxlokk F.C. in 2007. After that, Justin had great spells at foreign clubs such as Chaidari, Sheffield United, Ferencvaros and Kerkyra, before once again he returned in Malta to join Mosta F.C. in 2012.

Since then, Justin always played in Malta with several clubs such as Birkirkara, Hibernians, Floriana, Gzira United and Santa Lucia. The former international goalkeeper also made 55 appearances for the Maltese National Team.