[14][16] One day, Mooy expressed his enjoyment of playing with friends to his mother, who promptly registered him with the Carlingford Redbacks, a club that his German stepfather, Alan Todd, would soon join to coach his team.

[31] On 17 December 2011, Mooy made his return, coming as a substitute, in a 1–1 draw against Motherwell[32] and the next game, he scored his first league goal for the club against Rangers at St Mirren Park on Christmas Eve 2011.

The official media launch took place at Parramatta Stadium, where he was introduced alongside two players, Tarek Elrich and Kwabena Appiah, ahead of the 2012–13 A-League season.

[47][48] In January 2014, Mooy handed in a request for a transfer, effective immediately, to Western Sydney Wanderers after being unhappy with inconsistent game time during the season.

[52] Two weeks later, Mooy was subbed on in his second consecutive Grand Final where he was booked in extra time before losing 2–1 to Brisbane Roar in front of 51,153 attendees at Suncorp Stadium.

[99] Following the match, a young fan gifted Mooy £5 for his performance, which he later donated to the club's Town Foundation—a charitable organization dedicated to supporting children in the local community.

[102] After recovering from bad form in the early stages of the 2018–19 season, Mooy scored two goals, his second being a free kick past Rui Patrício, to secure a 2–0 win against Wolverhampton Wanderers, sending his side above the relegation zone.

[111] On 19 October, Mooy was sent off for the first time in his club career after receiving two bookings in the 30th and 35th minute (for fouling Jack Grealish) in Brighton's eventual 2–1 loss to Aston Villa.

[140] On 26 February, Mooy started in Celtic's 2–1 victory over Rangers in the League Cup final, contributing to the build-up of the second goal and securing his side's first trophy of the season.

[141][142] Continuing on his form in the Scottish Cup, on 11 March, Mooy scored the opening goal within just over 100 seconds, to lead his side into an eventual 3–0 quarter finals victory over Hearts.

[146] On 7 May, Mooy helped Celtic retain the Scottish Premiership title, achieving a double, after assisting Oh Hyeon-gyu brace to ensure a 2–0 victory against Hearts at home.

[164] On 7 December 2012, Mooy made his senior debut for Australia at Hong Kong Stadium, scoring the opening goal in a 9–0 victory against Guam in the second preliminary round of the East Asian Cup.

[168] However, he was ultimately excluded from the final selection and instead participated in a 12-day camp at New York University in Abu Dhabi alongside the other 22 unselected players, playing scheduled friendlies from 11 to 18 January 2015.

Mooy's presence in midfield was instrumental in limiting the opposition's scoring opportunities and creating key chances in the attacking front as his side lost 2–1 at full-time.

[187][188] Unfortunately, due to their lack of attacking presence, Australia fell bottom of the group, only able to score their goals from the penalty spot following a 1–1 draw against Denmark and a 2–0 defeat to Peru.

[189] Following the tournament, Mooy would miss the entirety of the Asian Cup campaign in January 2019 due to a torn medial collateral ligament in his right knee which was expected to keep him out for three months.

[194][195] However, after 18-months of no international football due to COVID-19, Mooy made his return with Australia in August 2021 after being added to the 27-man squad set to play in the remaining group matches and third round fixtures.

[200] After his side's loss, Mooy was recalled back to his club, Shanghai, to return into quarantine due to the Chinese Government's rules and regulations in the pandemic which interfered with his playing time at international level.

[207] A week forward, he started in the crucial match against the United Arab Emirates in the World Cup qualification fourth round after his nation finished third in the group stage of round three; Mooy was involved in the winning goal as his corner was deflected off towards Ajdin Hrustic, whose goal gave Australia the lead in the 84th minute and ensured a 2–1 win at Ahmad bin Ali Stadium.

[213] In the final match against Denmark, Mooy continued his good form, playing a pivotal role in midfield to influence a 1–0 win, qualifying to the Round of 16 for the first time since 2006.

[15] As Mooy moved to different clubs, including Western Sydney Wanderers, Melbourne City, Huddersfield Town, Brighton, Shanghai Port, and Celtic, his playing style evolved.

[223][224] He displayed his versatility by playing in various positions, including the right centre midfield role in Shanghai's formations and as a quarterback-like player for Huddersfield, orchestrating the team's attacks.

[231][232] David Wagner, former Huddersfield Town manager, praised Mooy for his technical ability and defensive qualities, highlighting the unusual playing style that made him stand out.

[233] Pep Guardiola, renowned as one of the top coaches in world football, praised Mooy during his loan spell at Huddersfield Town, describing his performances as "amazing.

Former adult film star Mia Khalifa, a notable West Ham fan, included Mooy in her top three favourite footballers alongside legends Zinedine Zidane and David Beckham.

"[243][244] During his early years, his mother, Sam, played an important role in Mooy's daily routine, driving him to and from training sessions since he didn't have a driver's license at the time.

When he turned 21 during his time in Scotland, Aaron opted for a meaningful celebration for his coming of age by requesting his 15-year-old brother, Alex, to join him rather than indulging in excessive drinking at a local pub.

[252] In honour of his daughter, Skylar, Aaron Mooy dedicated a celebration after scoring his fourth goal for Celtic, forming an "S" gesture, symbolizing her name.

[254] His uncle, Paul Cosgrove, is a senior constable police officer at Quakers Hill and his father in law, Ian, is a lifelong Celtic supporter.

[258] The name "Mooy," which Aaron's grandfather Australianized from "Mooij" after immigrating from Holland to Australia, holds significant meaning to him, representing his connection to his family's roots.