Jacob Mahler

Young Lions

A youth product of the National Football Academy in Singapore, Mahler moved to Young Lions in 2018. Mahler made his professional debut for Young Lions in a 1–3 Singapore Premier League lost to Geylang International on 4 July 2018. Mahler was named the club captain from the 2019 season onwards. in the 2022 season, during a match against Tampines Rovers FC, Mahler suffered an anterior cruciate ligament (ACL) and meniscus tear which took him out for the rest of the year.

Madura United

On 19 May 2023, Mahler joined Indonesia Liga 1 club, Madura United becoming the 10th Singaporean to play in the Indonesian top-flight league. On 23 July 2023, Mahler scored his first goal for the club against Persis Solo coming from a set piece cross from Francisco Rivera. Mahler was named in three consecutive "Team of the Week" from gameweek 4 to gameweek 6.

Muangthong United

On 5 July 2024, Mahler moved to Thai League 1 club Muangthong United. On 25 August, he made his debut for the club in a 2–0 win over Ratchaburi. Mahler later sustained a more severe knee injury – ACL, Medial collateral ligament (MCL), and additional ligament damage – which required two surgeries. The injuries resulted in Mahler missing the entire season.

Tampines Rovers

On 29 June 2025, Mahler returned to Singapore to sign with Tampines Rovers.

Mahler made his professional debut for the Singapore national team in a friendly 2–0 win over Fiji on 11 September 2018. He scored his first goal for Singapore when he collected his second cap against Cambodia on 16 October 2018 in an eventual 1–2 win. Mahler made his AFF Championship debut in the 2018 campaign on 9 November, with a 1–0 loss over Philippines. In 2022, Mahler was named captain of the SEA Games Under-23 national football squad after he was called up the for 2021 SEA Games in Hanoi, Vietnam. He was later withdrawn from the team after he suffered an anterior cruciate ligament tear during his club's match in the 2022 season. After a five years absence, on 8 September 2023, Mahler made his return to the senior squad in the starting line up against Tajikistan. On 12 October, Mahler scored his second international goal in a 2–1 win against Guam in the 2026 FIFA World Cup qualification. On 21 March 2024, Mahler came on as a substitute and scored at the 81st minute to equalise the scoreline to 2–2 during a 2026 FIFA World Cup qualification match against China.

Club

As of match played 15 September 2024

International

Scores and results list Singapore's goal tally first.

Mahler was born in Copenhagen, Denmark to a Danish father and Singaporean mother. His family moved to Jakarta, Indonesia due to his parents work but soon returned to Singapore when he was four. He attended St. Joseph's Institution (SJI) before graduating from Temasek Polytechnic (TP) with a Diploma in Aerospace Electronics. Mahler is a big fan of Manchester United and had cited that he used to emulate the playing style of his favourite player, Paul Scholes.