In 2004, Commonwealth received its 1st Ministry of Education's Sustained Achievement Award for both uniformed groups and the performing arts.

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

[5] Commonwealth Secondary School had consistently stellar performances in the Singapore-Cambridge GCE Ordinary Level examinations.

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

One of the projects was the adoption of the mangrove boardwalk trail in the Sungei Buloh Wetland Reserve as part of the Adopt-A-Park Scheme launched by the National Parks Board.

A group of teachers was identified to develop a customised environmental education curriculum for the school, starting with the Secondary One students in 2007.

2006 also saw the school clinching the Lotus Award in the Singapore Environment Council's Green Audit.

[2] On 28 March 2014, the school celebrated Earth Hour with the Amazing Spider man II cast, Andrew Garfield and Jamie Foxx.

The two superstars not only interacted with the 1400-strong audience, they also did their part for the environment by planting a sugar apple and giant lemon bush in the school's Gift of Life Garden.

2009 was a record-breaking year for the school, with three aesthetic groups attaining the highest accolade, Gold with Honours.

[citation needed] The hockey team was ranked among the top eight schools in Singapore for the third year running.

[citation needed] The National Cadet Corps of CWSS had maintained high standards for the past years, attaining gold award for unit performance in 2005, 2008 and 2009.

Members of PTN are involved in planning school events such as a funfair, and the seniors' graduation night.