[1] Founded by the Franciscan Missionaries of Mary (FMM) sisters in 1959, it is affiliated to Catholic Junior College.

From 1960 to 1961, a three-storey building was constructed at the 7+1⁄4 mile mark of Upper Serangoon, with an office, science laboratories, 18 classrooms and a common room for teachers.

[7] In March 1990, the school moved from Upper Serangoon Road into Pasir Ris New Town, with the official opening ceremony held on 11 July 1992.

After students from the Express course and Secondary 5 students from the Normal-Academic course receive their Singapore-Cambridge GCE Ordinary Level examination results, they can apply for admission to Catholic Junior College and receive 2 bonus points due to affiliation.

[16] For the top, all students wear a white unisex, short-sleeved, buttoned-down shirt, with the collar band accented in the colour of the school's traditional blue.

For the bottoms, all girls wear knee-length A-Line skirts solid in the colour of the school's traditional blue.

Students pin a simple plastic, rectangular tag, engraved with their name in Sans-serif font, above their breast pocket on their left, coloured according to the year of their enrolment.

In the past, the school's crest was also engraved on the left of the tag, but this design choice has long since been discontinued.

For Physical Education (PE) classes, students change into a sporting outfit consisting of a round neck T-shirt in the colourway of the school's traditional blue and white, plus the student's house colours (discontinued), paired with black short trousers.

It is a dark blue, cyan and white shirt with the school logo at where the breast pocket would be.

Possible disciplinary actions include detention class, caning (for male students only) or suspension, depending on the seriousness of the offence committed and the frequency of its recurrence.

Other serious offences include (but are not limited to) vandalism, gang-related behaviour, arson, forgery, causing hurt to others or any other case involving the Police.

A banner contains the Latin words, Ad Veritatem Per Caritatem (To truth (God) through charity) below the logo.

The school holds the event yearly with classes from Secondary 1 to 3 setting up food and games stalls.

A blood donation drive led by the school's St John's Brigade (CCA group) is also held.

Students of the school who are 16 years or older can donate, including members of the public such as parents, or alumni who attend the Carnival.

There is a lucky draw held at the end of the carnival for all ticket holders, where students, the public and teachers can win multiple prizes.

Annually, the schools organises overseas trips for its students to Vietnam, Malaysia, China and Indonesia.

[18] The Express Course is a nationwide four-year programme that leads up to the Singapore-Cambridge GCE Ordinary Level examination.

[23] Students in Hai Sing Catholic School offer 5-7 subjects in the Singapore-Cambridge GCE Normal Level examination.

Hai Sing Catholic School has won a wide array of prizes and attained many achievements in multiple diverse types of academic-based competitions.In the C.B.

(Seen in the photo beside)[24] In the Singapore Mathematical Olympiad (SMO) 2017, the school secured 1 Bronze medal along with 3 Honourable Mentions.

The school has won multiple World Champion Titles and Gold awards at the championships they have taken part in.

[12] There are in total 4 physical sport Co-curricular activities offered at Hai Sing Catholic School.

[29] The Taekwondo Co-curricular activity has received 1 Gold, 7 Bronze and 7 SSSC Colours Award at the National Inter-School TKD (Kyorugi and Poomsae) Competitions.

[29] Most notably, the Singapore Youth Flying Club received the Champion award for the Electronic Control Line at the SYFC Inter-school Aero-modelling Competition 2015.

[29] At the Singapore Youth Central Judging Competition 2015, the Malay Dance and Choir CCAs got a Certificate of Distinction.

At the Inter-Unit .22 Revolver Shooting Competition 2015 (Finals), the Girls' Team received a Gold award and a Khoo Boon Hui Challenge Trophy.