[5] As a child growing up in Melbourne's Western Suburbs, Leckie actually aspired to play Australian rules football, his family supporting Essendon and Box Hill, however at 11 years old a change to a school in Sunshine North with a more multicultural student body and close friends inspired him to take up football and he "never looked back".

[9] He followed this up by scoring his second goal in as many games against Shandong Luneng in Adelaide's 2–0 win on Match Day 2 of the Champions League.

[11] Leckie started the 2010–11 season with a bang, scoring twice in Adelaide's first five games, earning wide praise for his entertaining and robust style of play and winning the favour of the Australian U19 side for their competing in the 2010 AFC Under-19 championships.

On 3 June 2013, Leckie made his loan move to FSV Frankfurt permanent, signing a three-year contract that would run until 2016.

[16] Leckie scored two goals on his debut for Hertha BSC on matchday one of the 2017–18 Bundesliga season against VfB Stuttgart in a 2–0 home victory.

[21] In August 2009, Leckie was selected to represent Australia in the AFF U19 Youth Championship 2009, where he opened up the score-sheet in the 4–1 win over hosts, Vietnam, in the semi-finals.

Ex-Australian National Coach, Pim Verbeek, named Leckie in the 25 man Socceroos squad for the AFC Asian Cup 2011 Qualifier against Indonesia.

[24] Ex-Australian national coach Holger Osieck included Leckie in the squad for the international friendly against the Republic of Korea on 14 November 2012.

Australian National Coach, Ange Postecoglou, included Leckie in the squad for the international friendly against Costa Rica on 19 November 2013.

[34] In the third and final crucial group game against Denmark, he scored the winner in a 1–0 victory that ensured qualification to the round of 16.