Early years Maclaren grew up in the north-western suburbs of
Melbourne. He first joined the junior side of local team Sunbury United at the early age of four or five, then switched to the youth ranks of nearby Victorian Premier League (now
National Premier Leagues Victoria) side
Green Gully in 2003, where although he continued to play against older players, his team was very successful, at one point winning around 50 games in a row.
Blackburn Rovers In July 2009, aged 15, he was invited to trial for
Blackburn Rovers' under-16 squad. In his first trial match he scored two goals against
Derby County's under-16 squad, followed by a
hat-trick against
Manchester United, which resulted in a contract offer from Rovers. Maclaren benefited from the mentorship of fellow Australians
Vince Grella and
Brett Emerton at Blackburn, where he soon progressed to be a regular under-21 squad player and training with the senior team. However, after four years in England having not broken into the first team, he was released by Rovers at the end of the 2012–13 season.
Perth Glory Seeking first-team game time, Maclaren elected to return to Australia and signed a three-year contract with
A-League club
Perth Glory at the beginning of the 2013–14 season. Maclaren made his Perth Glory debut, where he played 90 minutes, in a 3–1 loss against
Adelaide United. Maclaren then scored his first goal for Perth Glory weeks later, on 27 October 2013, in a 1–0 win over
Melbourne City and scored his second Perth Glory goal on 23 November 2013 The 2014–15 season was his breakout year, scoring 10 goals in 23 appearances across all competitions, and earning the April nomination for the league's young player of the year award. He also made a number of appearances in the
National Premier Leagues side scoring 11 goals in just five games. Maclaren scored his first senior club hat-trick, scoring all three of Glory's goals in a 3–1 win against Melbourne City on 19 April 2015. At the end of the 2014–15 season, in the fallout from the
Perth Glory salary cap scandal, Glory agreed to release all contracted players who wished to leave the club, with the sole exception of Maclaren. In response, he lodged a formal breach-of-contract notice against Perth Glory to the players' Union,
Professional Footballers Australia. Maclaren was subsequently released by Glory on 29 June 2015.
Brisbane Roar in 2015 During the A-League off-season, on 5 July 2015,
Brisbane Roar signed Maclaren to a two-year deal. Maclaren made his debut with the Roar against the
Western Sydney Wanderers on 8 October 2015. In the same game, he scored a brace for the Roar, with goals in the 9th and 34th minutes of the match. Later that season Maclaren reached his 50th senior A-League appearance, scoring a goal and assisting another against his former club, Perth Glory. He scored his second senior club hat-trick in a win against
Melbourne Victory on 12 March 2016. Maclaren finished the A-League regular season with 18 goals, second in the Golden Boot race to
Melbourne City's
Uruguayan striker
Bruno Fornaroli, however his season tally was enough to become the all-time A-League record for an Australian player. Maclaren scored two more goals in the finals series to make his final club goal count 20 from 25 games. At the end of the 2015–16 season, he was awarded as the Young Player of the Year by the FFA. Maclaren scored 19 goals for the Roar in the
2016–17 A-League regular season, tying with
Besart Berisha for the Golden Boot.
Darmstadt 98 in 2017 In May 2017, Maclaren joined German
2. Bundesliga club
Darmstadt 98 signing a three-year deal. He made his debut in the second round of the season as a 63rd minute substitution in a 1–1 draw away to
FC Kaiserslautern on 4 August.
Loans to Hibernian Maclaren was loaned to Scottish club
Hibernian in January 2018, in the hope that more playing time would boost his chances of being selected by Australia for the
2018 FIFA World Cup. He made his
Scottish Premiership debut in a 1–0 win at
Dundee on 24 January. Maclaren scored his first goal for Hibs on 3 February, converting a match-winning
penalty against
Rangers. He scored the second goal in a 2–0 win for Hibs in an
Edinburgh derby on 9 March, and helped to delay
Celtic's title celebrations by scoring the first goal in a 2–1 win for Hibs on 21 April. He ended his season in Scotland by scoring a
hat-trick in a 5–5 draw with Rangers. After the loan spell ended, Maclaren said that he hoped Darmstadt would make him available for transfer. On 3 August, Maclaren returned to Hibernian on a season-long loan. This spell was less productive, as Maclaren only scored one goal and he struggled to hold down a regular place in the starting lineup.
Melbourne City On 31 January 2019, Maclaren signed for
A-League club
Melbourne City on a marquee deal to see him at the club till May 2022. He scored in his first game for City with a backheel against
Adelaide United on 9 February. He won the Golden Boot that season with 22 goals, three more than the nearest competitor,
Adam Le Fondre. On 6 March 2021, Maclaren scored and assisted two in
Melbourne City's 6–0 away win over
city rivals Melbourne Victory. On the next meeting on 17 April 2021, he became the first player to score five goals in the A-League regular season history, and just the second of all time, as the hosts won 7–0. He became Melbourne City's record goalscorer with 58 goals on 13 May 2021, when his team won 4–1 against
Adelaide United at home overtaking
Bruno Fornaroli. After 5 and a half seasons at the club, on 30 April 2024 it was announced that Maclaren would leave Melbourne City at the conclusion of the
2023–24 A-League season, in the lead up to the club's elimination final against derby rivals
Melbourne Victory. Maclaren played his final match for Melbourne City in a
Melbourne Derby elimination final against
Melbourne Victory. Maclaren was substituted off in the 75th minute of the match, having registered just 8 touches in the match, as Melbourne City lost 3–2 on penalties after the match ended 1–1 in regulation time.
Mohun Bagan In July 2024, Maclaren signed with
Indian Super League club
Mohun Bagan on a two-year deal. He made his debut for the club on 23 September, coming on as an 80th minute substitute in a 3–2 win against
NorthEast United. Maclaren scored his first goal for Mohun Bagan on 5 October, heading the opening goal in the 8th minute of a 3–0 win over city rivals
Mohammedan. In the following match on 19 October, he scored the opening goal in the
Kolkata Derby against arch-rivals
East Bengal. On 12 April 2025, he scored the
extra time winner in a 2–1 victory over
Bengaluru FC in the
2025 ISL Cup final, and was named the Player of the Match. On 6 March 2026, Mclaren scored four goals in a 5–1 win over
Odisha FC, his first ever ISL hat-trick. ==International career==