Born in Sydney, Amini played youth football with the Australian Institute of Sport before starting his professional career with Central Coast Mariners in the A-League.

[5][6] Amini made his debut for the senior team in a friendly against fellow Gosford club Central Coast Lightning which the Mariners won 7–1.

Amini's excellent form throughout the 2010–11 A-League season attracted major interest from overseas clubs Borussia Dortmund and Bayern Munich.

Subsequently it was announced that Amini was to spend two weeks on trial with Borussia Dortmund in preparation for the 2011 FIFA U-20 World Cup in July with a view of signing a long term deal with the Bundesliga club.

[8][9] Only days into his trial Borussia Dortmund publicly announced that the youngster had caught the eye of first team manager Jürgen Klopp stating that "he can definitely play football and is a really great talent.

However, Amini would initially be loaned to Central Coast Mariners until 31 May 2012, making him eligible to play for the club during the 2011–12 A-League season as well as the group stage of the Asian Champions League.

[19] On 24 December 2021, Amini signed a six-month deal with A-League Men club Sydney FC as an injury replacement for Luke Brattan.

[22] Having not made an appearance in the 2024-25 season due to a knee injury, Amini's contract with Perth was terminated on 28 December 2024, ahead of the January transfer window.

On 23 March 2011, after impressing on trial at Borussia Dortmund, Amini was called up to the Australian national side training camp by Head Coach Holger Osieck which was being held in Germany.

[10] Amini was named among the 43 players squad to represent Afghanistan for 2014 AFC Challenge Cup preparations camp in Qatar, but he refused the call saying "I only want to play for Australia if I get the chance".