On 4 November 1912, the school officially opened in a house located at 18 Weld Road (now known as Jalan Raja Chulan) with the principal, Miss Chitty who took charge of women's work and 3 enrolments.

In the same year, the 9-acre (36,000 m2) site of Weld Hill Road was bought under the name of the Bishop of Singapore and Malaya, using a sum of £36000.

In September of the same year, the school moved again to a bungalow in 7 Treacher Road (now known as Jalan Sultan Ismail), with a total of 54 morning session students and 4 boarders.

The school reopened with Miss Edna Yzelman as the acting principal on 18 October 1945 after the Japanese Army retreated from Malaya towards the end of World War II.

The school later received a visit from the Governor of Malaya, Sir Edward Gent on 6 April 1946.

As school reopened on 20 January 1947, full classes resumed with Agnes Pinnick as the acting principal.

There was much progress in the school that temporary classrooms were established near the road for the accommodation of increasing enrolment.

Later on 1 November 1957, the Revd Tan Sri Roland Koh (subsequently the first Bishop after the Diocese of West Malaysia was formed in 1970) opened more new classrooms for the primary education students.

In conjunction with the incorporation of Rahman Talib Report into Education Act 1961, [3] the upper secondary (Form 4 and 5) students were split into two streams: Arts and Science.

The school was renovated again for the last time in the Jalan Tengah premise - two classrooms and two specialist rooms were established.

The relocation plan began in 1995, when the Lion Group bought the school land and negotiations were made with the Ministry of Education.

December of the same year marked the beginning of the large scale shift to the new 9-acre (36,000 m2) site at Taman Intan Baiduri, Selayang.

Finally on 31 March, the Anglican Diocese of West Malaysia handed the keys of the old school to the Lion Group.

On 15 July, the school PA system was fully establishment using the funds of Pesta Ria (translated as "Fun Fair").

Through the generosity of St. Mary's Association, the school hall was already equipped with motorised stage curtains and a wood panelling façade by March 2000.

Another new school building was officially opened by Tun Dr. Siti Hasmah and Datin Paduka Seri Endon Mahmood.

A farewell ceremony, organised by the school, Parent-Teacher Association and the Board of Governors, was held for Miss Goh's retirement on 21 October 2005.

As of 1948, they were renamed after St. Mary's past principals as follows:[6] In the 2009 ITF 14 & Under Asian Championship organised by Sarawak Lawn Tennis Association (SLTA) held from 10 to 21 January 2009, Archnaah d/o Rajan, a student of the school, managed to achieve fifth place in the Girls' single.

[8] In the 2016 SEA Forensics held from 18 to 20 February, Lohsshini Sethu Pathy and Vanessa Tai Tsuk Yinn, students of the school, achieved the gold medal in Duet Acting.