LionsXII debuted in the 2012 Malaysia Super League on 10 January 2012 with a 1–2 home defeat to defending champions Kelantan FA.

The main aim was to develop the under-23 players and prepare them for the upcoming 2013 Southeast Asian Games that would be held at the end of the year.

[11] Singapore's Prime Minister, Lee Hsien Loong was present for the match played in front of a sold-out crowd at the Jalan Besar Stadium.

The Malaysia Super League trophy was also brought to the stadium as the LionsXII received it on home soil after the final whistle.

The club chalked up their best home record (10 wins and 1 draw) in the league, making Jalan Besar Stadium a fortress.

At that time, coach V. Sundramoorthy was said to leave LionsXII at the end of the season to take charge of second tier Malaysian Premier League side, Negeri Sembilan FA.

[12] On 28 September, LionsXII narrowed a 1–0 victory over ATM FA in the first leg of the quarter-finals of the 2013 Malaysia Cup but squandered to a 1–4 mauling to the opponent in the return tie on 4 October.

Sufian Anuar and Khairul Amri were recalled to join LionsXII following the exit of Baihakki Khaizan, Hariss Harun, and Shahril Ishak to Malaysian side, Johor Darul Ta'zim.

On 7 December 2013, former Johor Darul Ta'zim coach and ex-Singapore international Fandi Ahmad was offered a three-year contract at the helm of the LionsXII, despite initial denials by the FAS.

[17][18] On 25 November 2015, FAM reportedly decided not to extend their Memorandum of Understanding (MoU) with the Football Association of Singapore (FAS), which was signed in 2011.

[19] It was announced by the Football Association of Singapore that LionsXII were to be disbanded at the end of the 2015 season and the players would have to find a new club in 2016.

Using the lines as contrast, the lion shows ferocity and aggressiveness, resembling the fighting spirit and determination of all the players in the squad.

However, during the semi-final Piala Malaysia game between ATM FA and LionsXII in Stadium Majlis Perbandaran Selayang in which they were defeated on penalties and bowed out of the tournament, they wore a combination of the white top and blue bottom.

However, ATM once again shattered the double wish as they overturned the deficit sustained in the first leg of the 2013 Malaysia Cup quarter-finals and emerged triumphant 4–2 over the LionsXII.

Along the way, long standing issues with Malaysia Super League participants PKNS of Selangor and T-Team of Terengganu also arose.

Other partners on social media include Temasek Polytechnic, The Cage, X-League (Singapore) and Tiger Beer Football.

On 5 January 2012, Football Association of Singapore announced the appointment of StarHub as the Official Broadcaster and Principal Sponsor of LionsXII.

[29] Two days after the announcement of the kit, LionsXII sealed a second major sponsorship deal, with news that SilkPro will fund the Singapore outfit to the tune of S$1m during its debut season in Liga Super.

V. Sundramoorthy and Fandi Ahmad were both part of the Singapore Lions 'Dream Team' that won promotion back to the M-league Division 1 and finished as runners-up to Kedah in the Piala Malaysia Final in 1993.

The following year, led by Fandi, Singapore overcame the absence of Sundram to win the 1994 M-League and Piala Malaysia double.