The story of the Trinity College Library begins in 1875 with the forming of the Trinity College Literary Association. The Secretary of the Literary Association also acted as the Librarian and the books were housed in Collin’s Hall. In 1882 during Rev. Garrett’s time, it was transferred from the Literary Association to the school. 

A new building was put up in 1913 for the Library and Bursary. A full-time Librarian was appointed for the first time. The building was ceremonially opened by Mrs. T.B.L. Moonemalle on 12th December. 

Rev. Campbell in 1925 in his desire to create an undergraduate atmosphere turned his attention to the library. A committee was appointed and a competition was held to design a book plate to be used in the library. Bud Jansze (Brother of Mr.Vernon Jansze) won this competition and this design is used until today. 

In 1939 the library building was demolished to make way for the new hall. The books were transferred to a temporary home in the Junior Common Room on the ground floor of Alison and continued till a spacious new library was completed by Mr. Norman Walter with the generosity of the Senanayake brothers. On 11th November 1955 the Minister of Finance Mr. M.D.H. Jayawardena unveiled a portrait of the late Mr. Milton Senanayake in the College Library marking the opening of the Milton Senanayake Memorial Library. It was donated to the College by Messers E.L.Senanayake, E.R.Senanayake and Dr.J.E.Senanayake in memory of their brother Milton, who died in England at the age of 24 years. 

The Library Council was officially started in 1951. The books were catalogued by Mr. Vernon Jansze according to the “Dewy’ decimal system in 1955. Mrs. S.Jayasekera and. Mrs. Herathge served as librarians subsequently. Mrs. S Jayasekera returned as librarian for a further tenure in 1989 and the Library Archives and Museum Project was begun with the help of Hon. Lakshman Kadirgamar. The second phase of the project was the Library Extension Project with the Auditorium and the Language Lab. Though she left in 1996 it bore fruit when Mrs. S. Kuruwita was appointed as the Librarian in 1997. The Auditorium was ceremonially opened by Hon. Lakshman Kadirgamar on 14th February 1997. In the year 2000 the Archives was moved from the TV room to the present place. At the end of 2015 the library was refurbished by the Batch of 1996 into a creative learning space with modern facilities.