The school finally acquired its own building at the current location on 72 S.N. Banerjee Road (then Corporation Street) in 1893, thanks, in large measure, to the generosity of a man who could be regarded as the Chief Patron of the school: Sir Robert Laidlaw KT (1856-1917). M.P. for the East Renfrewshire, Scotland, from 1906-1910 and founder-chairman of the great business houses ‘Whiteway, Laidlaw and Co.’ and the ‘Duncan Durian Rubber Estate, Ltd’, Sir Laidlaw donated the land and erected the Main building in 1893 and the Renfrew House in 1902. He endowed the school with the 3 magnificent ‘Waverley Mansions’ in 1903 and established the Calcutta Boys' School Endowment Trust in 1904.

THE HOUSE SYSTEM: was inaugurated in 1916. The names of the houses were THOBURN (Red), LAIDLAW (Green), WARNE (Light Blue) and PRITCHARD (Dark Blue). Bishop F.W. Warne, a Canadian by birth, arrived in Kolkata as Pastor of Thoburn Methodist Church in 1888 and played an active role in social work in the city and also in sustaining CBS in its early years as a board member and thereafter as Chairman from 1900 (having been elected Bishop of the Methodist Episcopal Church). Mr. C.J.A. Pritchard was a valued member of the school committee. Later, however, in 1933, HENDERSON (Blue) House replaced Pritchard House in honour of Reverend George S. Henderson, an eminent Pastor of Thoburn Church and founder Chaplain of CBS, and the colour of WARNE House was changed from Light Blue to Gold.

In the list of Principals two great names stand out- Mr. H.C. Fritchley and his son-in-law, Mr. C. Hicks. Till 1931 when Mr. Fritchley (the first Anglo-Indian Principal of CBS) assumed office, there had been a series of foreign Principals who were mainly English and Church men. In 1931, when the school was suffering an acute financial crunch,Mr. Horace Christopher Fritchley , a teacher in CBS since 1912, was appointed Principal. He introduced a series of austere disciplines, abolished the system of giving out prizes on Speech Day & Sports’ Day and taught his staff and pupils “to love the game beyond the prize”. Within a very brief period, Calcutta Boys' School had cleared all debts and was financially stable. The Middle building, erected in 1962, has been named “Fritchley Building to commemorate the dedicated services of Mr. Horace C. Fritchley. In 1953, Mr. Clifford Hicks, a teacher and Headmaster of CBS, took over as Principal. During his tenure of 22 years, Mr. Hicks became a legendary figure in the field of education. He was nominated as Member of the West Bengal Assembly in 1967. Mr.

Hicks emphasised both high morals and high academic standards. If he is remembered for raising the school to a high level in terms of academic results and strict discipline, he is also remembered for his inspiring Chapel messages. The school library has been dedicated to the memory of Mr. Clifford Hicks.

The present Principal & Secretary, Mr. Raja McGee assumed office in 2007. His vision of “CBS Beyond Moulali” took shape when Calcutta Boys' School extended beyond the mother campus on 72 S. N. Banerjee Road to disseminate the light of education in other parts of West Bengal. The extension campuses (branch schools) were established at Sonarpur in 2008, in Beliaghata in 2010 and in Asansol in 2015 and at Shantiniketan, Bolpur.

Calcutta Boys' School together with its extension campuses is distinctively a Christian Minority, Anglo-Indian, heritage institution, under the control and authority of the Calcutta Boys' School Educational Society, a registered non-profit, charitable society of the Bengal Regional Conference of the Methodist Church in India, committed to providing holistic education and the production of useful and faithful citizens of India.