1902 Trinity Grammar School was founded on the 14th November, 1902 at a meeting of the following members of Holy Trinity Parish: The Venerable Archdeacon Hindley, The Rev’d H. Merrick Long, Drs H.O. Cowen, W. Kent Hughes and E.M. Inglis and Mr W.J. Roberts.
1903 The School opened in the Parish Hall of Holy Trinity, Kew with the Rev’d Edward Taffs as first Headmaster. The average number of boys in the first year was 23.
1904 The Rev’d G.M. Long became Headmaster.
1906 The School moved to ‘Roxeth’ (now Henty House).
1907 Arnold Hall and classrooms were opened in February and Trinity was registered as a Public School of the Church of England. First Edition of the Mitre was published.
1908 ‘Molina’ (now Merritt House and previously Kew High School), was leased from Mr John Henning Thompson, its owner and Headmaster.
1909 A science laboratory was built on the west side of Arnold Hall. The School Song was written, and the O.T.G.A. founded.
1911 The Rev’d G.M. Long left Trinity to become Bishop of Bathurst and the Rev’d A.W. Tonge was appointed Headmaster.
1915 The building presently housing the Technical Centre was completed in front of Arnold Hall.
1917 The Rev’d A.W. Tonge resigned to become an army Chaplain and Mr Frank Shann became Headmaster. The House system was introduced.
1921 The War Memorial Library was built. The Associated Grammar Schools Sport competition began with Trinity winning the Tennis competition(and again in 1922).
1922 Average size of the school was 245.
1924 ‘Molina’ (now Merritt House) and ‘Elsinore’ (now Roberts House) were purchased.
1925 Arnold Hall, Henty House, Merritt House and Roberts House were renamed in honour of men who contributed significantly to Trinity’s development.
1926 The Junior School was built near Merritt House.
1929 St Paul’s choristers came to Trinity.
1940 A ‘Health Pavilion’ was completed near where the Shann Building stands.
1942 There were 230 boys at Trinity.
1943 Mr Frank Shann died and Mr Alfred Bright became Headmaster.
1945 Trinity won the football premiership for the first time.
1952 A second storey was added to the Junior School and opened as part of the School’s Jubilee celebrations.
1953 The Parents’ and Friends’ Hall was built between Merritt House and Xavier.
1956 The Art Building was completed and used as a Middle School.
1958 A number of schools left the AGSV to join the APS. Trinity won the Athletics premiership the first of twelve out of 13 years in a row.
1959 Mr Bright retired during the year and Mr John Leppitt was appointed Headmaster. The Robertson Science and Administration Building was opened.
1961 The Junior School Building (now the Watson Building) was extended towards Roberts House and provided art, music and other facilities. The tennis courts at the corner of Wellington and Charles Streets were removed and the Junior School Oval formed.
1962 School population reached 812.
1963 Trinity won four out of five premierships a feat which was achieved again in 1964.
1964 The Robertson Building was extended along Wellington Street
1968 The four storey Shann Building was constructed between Arnold Hall and Robertson Building. Cowombat Bushwalking Club formed. Construction of the Cornell Gymnasium.
1970 Changes to the P&F Hall. Second floor added to the Administration Building.
1973 Leppitt Outdoor Education Centre started at Lake Eppalock.
1975 The Boarding House was closed.
1976 Roberts House was converted for the Preparatory to Year 3 classes. Tonge Building was built in the area previously occupied by the War Memorial Library.
1979 Mr Leppitt retired and Mr Don Marles became Headmaster.
1980 The Swimming Pool was constructed.
1982 The Science Laboratories were reconstructed and named the Bright Laboratories. Merritt House was converted into the Music School. School population 998.
1983 The Bulleen Playing Fields opened.
1984 The P&F Hall was further developed and the Batson Quadrangle was paved.
1986 Reconstruction of Arnold Hall was completed and the area in front of it was paved.
1988 The Administration (Hindley Building) was redeveloped including construction of the Roof Garden.
1989 Further renovation of the P&F Hall took place, and the Poynter Building was finished.
1990 The Tuckshop on the West side of Charles Street was replaced by the Cafeteria on the ground floor of the Shann Building. Trinity won the first Hockey premiership.
1992 The Watson Building was extensively renovated to provide Junior School classrooms and offices. The Chapel of the Holy Trinity was built. Mr Don Marles retired as Headmaster.
1993 Mr Peter Crawley became Headmaster. Middle School classrooms in the Watson Building were re-constructed.
1993 Notebook computers introduced to the curriculum for Years 5, 7 and 9.
1995 Trinity won both the Athletics and Cricket premierships.
1996 The School purchased the former Kew Municipal Offices. Trinity won Basketball premiership, following this with equal success in 2000 and 2001.
1997 The Cohen Centre opened at Bulleen.
1998 The Centre for the Arts (former Kew Municipal Offices) opened. Mr Peter Crawley resigned as Headmaster.
1999 Early Learning Centre opened. Mr Richard Tudor appointed Headmaster. Bulleen playing fields renamed Marles Playing Fields.
2000 Radio technology incorporated in computers. For the first time, Trinity won the Soccer premiership.
2001 Synthetic Hockey Field opened at Marles Playing Fields. Construction of Science, Design and Technology building. Table Tennis premiership.
2002 School population just over 1200 boys – Prep to Year 12. Boarding re-introduced. Science, Technology and Design Centre opened in April. Start of Centenary Year celebrations November 14th,
2003 Centenary History book launched, August. Peter McIntyre Sports Centre opened, October. Licola Outdoor Site purchased.
2004 House System extended to 8 Houses.
2005 School purchased the Cotham Road site (formerly Stillwell Showroom)
2006 Messrs Bevan, Howell and Wootton each complete 40 years of teaching at Trinity 1967-2006. Centenary of Arnold Hall celebrated. Junior School Library relocated to lower level of Bright building. Billabong Restoration Project at Bulleen commenced.
2007 Premierships in Cricket, Hockey and Tennis (First time since 1968). Mr Colin Coutts retired as Head of Junior School with Mr Grant Nalder commencing in this role.
2009 New Summer uniform introduced.
2010 Rugby Premiership (first time), also premiers in Basketball and Athletics. Junior School Multi-Purpose Hall completed.