Along with Baihakki Khaizan, Shahril Ishak and Khairul Amri, Hassan was in the pioneer batch of the National Football Academy in 2000. Hassan has previously played for S.League clubs Tampines Rovers, Geylang United and Young Lions. According to an interview with him done in November 2007, he only started playing football competitively when he was 10, captaining his school, May Primary School. He later went on to represent Braddell Secondary Schoolfootball team as well. Hassan started out in football as a midfielder, only switching to between the sticks due to an asthma attack he suffered when he was 12. He also quipped that his happiest football memory was that, back in 1999, he scored the winning goal from the halfway line in a game that ended 2-1. Hassan joined the Eagles from the Singapore U-18 team and quickly cemented his spot in the first team, earning an S.League Young Player of the Year nomination for his confident performances and knack of pulling off blinding saves.
Singapore Armed Forces
In December 2011, Hassan joined SAFFC, after four years of service as Tampines Rovers' first-choice goalkeeper. His brilliant performances in the 2014 S.League season helped the Warriors win the S.League title. He also became the first goalkeeper to win the S.League Player of the Year award in 2014.
Hassan joined Army United F.C. for the 2015 Thai Premier League season. He made his debut in a 1-0 win over Royal Thai Navy F.C.. After a series of games in good form Hassan excelled in a surprising 1-0 away win at Suphanburi F.C., handing the latter side their first home defeat of the 2015 season as well as giving Hassan man-of-the-match award. After the game Suphanburi player Jakkaphan Pornsai said Hassan's performance was the main reason Suphanburi lost the match. In November 2015 Hassan signed a new two-year contract with the club. In December 2016 after the relegation of Army United from Thai League 1, Hassan Sunny was released from the team, ending two years of service at the Thai club.
Home United
Following his release from the Thai League side, Hassan signed for S.League side Home United FC.
Return to Army United
After the end of 2017 S.League season, Hassan re-signed for Army United and will play for them in the 2018 Thai League 2 season. He made his second debut for the club in the club's season opener against Nongbua Pitchaya on 10 February 2018, facing off against another Singaporean goalkeeper, Izwan Mahbud, who was also making his debut.
Return to Home United
After 2 seasons with Army United, Hassan penned a two-year deal with his former club, Home United.
International career
A graduate of the National Football Academy, Hassan forced his way into the Singapore against India after a superb debut season with Geylang United in 2003. With midfielder Shahril Ishak, defender Baihakki Khaizan and winger Muhammad Ridhuan, he is part of the 'NFA Gang of Four', the quartet which has played together since their early teenage years and earned senior international honours in 2003. He kept goal for the U-23 team that participated in the 2003 South-East Asian Games in Vietnam, before joining the Young Lions for the 2004 S.League season. His first appearance in a Lions shirt came in August 2003 when the young keeper replaced Rezal Hassan at half-time in a friendly against the Japan Olympic team. He had to wait until 18 February 2004 for his first cap for the Singapore though, which came against India in a World Cup qualifier. He has been a regular fixture in the national team, though only as a substitute for Lionel Lewis. However, due to his poor performances in the Merdeka Cup in 2007 with the Under-23 team, he was dropped for the friendly against UAE and Jasper Chan was called up in his place. His fine display at the 2007 SEA Games helped the Singapore Under-23 squad win the bronze medal - their first SEA Games medal since 1995. He performed extremely well in a World Cup Qualifier match against Saudi Arabia, but Singapore lost the match 2-0. On 28 July 2008, Hassan played the first half as part of a Singapore Selection side in a friendly match against the Brazil Olympics Team and made outstanding saves against Diego and Alexandre Pato shots, letting in only three goals. In 2016, UK based The Telegraph ranked him #18 on its list of the world's top 20 goalkeepers. He admitted to the Straits Times that he originally thought that it was a late April Fools joke. Hassan won his 75th cap for the Lions in early September 2018 against Mauritius.
Others
Singapore Selection Squad
Hassan was selected as part of the Singapore Selection squad for The Sultan of Selangor’s Cup held on 6 May 2017.
Career statistics
Club
. Caps and goals may not be correct.
Young Lions is ineligible for qualification to AFC competitions in their respective leagues.
