[2] On 9 September 1983, Mr Ho Kah Leong, Parliamentary Secretary, Ministry of Education, officiated the opening of the Auditorium and four classrooms.

On 2 June 2006, the upgraded campus was opened and blessed by Archbishop Nicholas Chia, head of the Catholic Church, Archdiocese of Singapore.

The upgraded campus featured an air-conditioned hall, a chapel, an alumni room, two theatres, and a roof garden.

The school completed the building of its Indoor Sports Hall in 2017, along with the setting up of an eco-garden and other green areas over the years.

HIHS celebrated the 125th anniversary of the establishment of the Holy Innocents' school in 2017, with the setting up of a time capsule and a newly designed heritage gallery in 2017.

Holy Innocents' High School believes in nurturing its students as Good Samaritans in the community.

In 2014, a group of students was reportedly lauded by members of the public removing debris from the middle of a busy road.

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

[10] Students who do well in the N Level exams can also apply for the Polytechnic Foundation Programme (PFP), or the ITE Direct Entry Scheme to Higher Nitec (DPP), which allows students to gain admission to relevant polytechnic diploma courses after the Higher Nitec course, subject to passing criteria.

[11] Students take English Language, Mathematics, Basic Mother Tongue and Computer Applications as compulsory subjects.

[citation needed] In each class, care representatives are appointed to watch out for classmates who might be emotionally stressed, anxious or disturbed.

[citation needed] Head of Department Ms Goh Lay Ching received a Commendation Medal (Pingat Kepujian) at the National Day Awards 2018.

[14] The alumni of HIHS play an important role in supporting school initiatives, as well as students who are deserving of financial aid.